Energy storage mechanism for an inhaler

ABSTRACT

An inhaler has a housing having a patient port and a cover rotatable about a cover axis between a closed position in which the cover covers the patient port, and an open position in which the patient port is accessible, a spring surrounding a medicament container in which the cover axis intersects the container, and in which the cover is configured to drive the resilient structure to store energy therein upon rotation from the closed position towards the open position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of United Kingdom Application No.1615186.2, filed Sep. 7, 2016, the disclosure of which is incorporatedby reference in its entirety herein.

FIELD

The present application concerns an energy storage mechanism for doserelease firing mechanisms in inhalers, in particular breath-actuatedmedicinal inhalers. The application also relates to inhalers, and inparticular medicinal inhalers containing some kind of medicamentcontainer, comprising such energy storage mechanisms.

BACKGROUND

Delivery of aerosolized medicament to the respiratory tract for thetreatment of respiratory and other diseases has been done usingpressurised metered dose inhalers (pMDI), dry powder inhalers (DPI), andnebulizers. pMDI inhalers are familiar to many patients who suffer fromeither asthma or chronic obstructive pulmonary disease (COPD). pMDIdevices often comprise a canister comprising an aluminium canister thatis sealed with a metering valve and contains a medicament formulation.Generally, the medicament formulation is pressurized and contains eitherfine particles of one or more medicinal compounds suspended in aliquefied hydrofluoroalkane (HFA) propellant, or a solution of one ormore medicinal compounds dissolved in a propellant/co-solvent system.Formulations incorporating dugs in both in solution and suspension formsare also known.

In a pulmonary pMDI, the sealed canister is provided to the patient inan actuator. The actuator is a generally L-shaped plastic mouldingcomprising a generally cylindrical vertical tube that surrounds thecanister plus a generally horizontal tube that forms a patient portion(e.g., a mouthpiece or nosepiece) that defines an inspiration (orinhalation) orifice. To use such an inhaler, the patient exhales, placesthe patient port into a body cavity (e.g., a mouth or nose) and then mayinhale to draw air through the inspiration orifice. Many such inhalersare of the pulmonary “press-and-breathe” type, where the patient pressesdown on the protruding end of the canister to operate the metering valveto release a metered dose of medicament from the canister into theinhaled air stream and thence through the mouthpiece into their lungs.This can require coordination of timing of inhalation and dose releaseif the emerging cloud of aerosolized medicament is to be taken farenough into the lungs to provide maximum therapeutic benefit. If thepatient releases the dose before inspiratory flow has been established,then a proportion of the drug is likely to be lost in the mouthpiece orthe patient's mouth. Conversely, if released much after the start ofinhalation, then the deeper regions of the lungs might already be fullof air and not penetrated by the following bolus of released medicamentaerosol.

Spacer devices have previously been devised which fit onto themouthpiece of a pMDI to reduce the velocity of the emergent plume ofmedicament aerosol and provide a volume in which it can expand and itspropellant can evaporate more completely. This serves to avoid some ofthe problems of coordination and the tendency for high throat depositioncaused by excessively fast drug particle inhalation. However, spacerdevices can be bulky and retain an excessive proportion of the drug ontheir walls, thereby reducing the dose that reaches the patient. Spacerdevices can also be highly sensitive to electrostatic charge, which canoften be strongly affected by the way in which they are washed or dried.

To overcome what can be quite a challenge for some patients, pMDI devicedesigns have been created that employ automatic breath-actuatedtriggering mechanisms, releasing a dose only in response to thepatient's inhaled breath. Typically, an energy storage means is providedwhich is primed by the user (for example by compressing a spring) andreleased by the triggering mechanism to provide an actuation load uponthe canister and thereby release the medicament. Once triggered, theinhaler needs to be reset for the next operation by a reset mechanism.

The AUTOHALER™ metered dose inhaler, available from 3M Company, St.Paul, Minn., USA and the EASIBREATHE™ inhaler, available from TevaPharmaceutical Industries Ltd., Israel, are two such pMDI devices thatuse breath-actuation to attempt to better coordinate dose release withinhalation. Many other inhaler breath-actuated mechanisms and resetmechanisms have been proposed, but tend to have one or more weaknessesor disadvantages, for example high component counts (and hence highmanufacturing costs), complexity (typically giving rise to difficultiesof assembly and/or complex dimensional tolerance stack-ups, etc.),performance issues (it is difficult to balance sensitivity (a lighttriggering force) against stability at rest and/or prior to inhalation)and/or excessive size and/or a less familiar or more awkward overallinhaler shape. Some of the existing devices employ mechanicalbreath-actuation systems that typically need to be tightly toleranced tobe both stable and yet also sensitive. This increases manufacturing costand can result in higher part rejection.

The issue of cost is a particular concern when consideringprice-sensitive markets such as those for generic drug products or inAsia. The embodiments of the present disclosure seeks to provide a resetmechanism for breath actuated inhalers at a manufacturing cost lowenough to make it highly attractive even in price sensitive markets.

A further issue of concern is that the energy storage means provided inthe inhaler may need to be fully primed before the device is triggered.Inadequate compression or extension of a spring (for example) may notstore sufficient energy to apply the desired force to the canister forthe travel required to fully release the medicament. Finally, it isbeneficial to discourage accidental or purposeful disassembly of theinhaler unit itself, to avoid malfunction and possibly damage caused bysuch disassembly.

EP0428380 discloses a breath-actuated inhaler within a housing, in whichthe inhaler is displaced by movement of a moveable cover against thebias of a cocking spring. A problem with this device is that the coveracts on the base of the mouthpiece to move the entire inhaler up againstthe bias of the spring. This can require a specially adapted inhalerbody and that the cover is fully rotated to go “over-centre”, whichcarries the risk of use before full spring compression.

WO 2005/094400 discloses an inhaler in which a tension spring isextended by rotation of a cover. Again, that the cover may need to befully rotated to fully tension the spring. Therefore use when“half-cocked” is possible. It will also be noted that the necessaryinclusion of a separate spring chamber makes the subject device bulky.

WO 2004/071563 discloses a dispensing device with an actuator, amouthpiece and a dust cap. Rotation of the dust cap moves a retainermember downwardly within the actuator towards the mouthpiece.

SUMMARY

An inhaler according to an embodiment of the present inventioncomprises:

a housing having a patient port and a cover rotatable about a cover axisbetween a closed position in which the cover covers the patient port,and an open position in which the patient port is accessible;

an energy storage arrangement within the housing, the energy storagearrangement comprising a resilient member and defining a void forreceiving a canister;

in which the cover axis intersects the void, and in which the cover isconfigured to drive the resilient member to store energy therein uponrotation from the closed position towards the open position.

Advantageously, the providing of such an arrangement results in a verycompact inhaler mechanism which can also generate a high degree of forcethrough rotation of the cover.

Preferably a cam is provided between the cover and the energy storagearrangement so as to produce a linear force (i.e. the force does notchange direction as the cover rotates) on the resilient member uponrotation of the cover. More preferably the cam comprises a cam memberdriven by the cover, the cam member being offset from the cover axis, inwhich the cam member is engaged with an engagement formation of theenergy storage arrangement. Preferably the resilient member defines theengagement formation. Advantageously, a cam arrangement converts arotational motion of the cover to a linear motion which can be used tocompress a linear spring.

Preferably the resilient member defines the void. Therefore, the springmay surround the canister in use, making a very compact arrangement.Preferably the resilient member is a generally tubular member having aresilient portion, which resilient portion may be an extensible portionconfigured to store energy in tension. The resilient portion maycomprise a cylindrical body having a plurality of openings definedtherein, desirably arranged in a plurality of offset rows. Preferablythe openings are circumferentially extending elongate slots in anotherwise unitary body. As such, the resilient member may be a mouldedspring.

Alternatively, the energy storage arrangement may comprise a sleevearranged to transfer force from the cover to the resilient member, withthe engagement formation for the cam defined on the sleeve. Theresilient member may be extensible to store energy in tension.

The sleeve may at least partially surround the resilient member, therebyallowing the resilient part to be axially longer and potentially storemore energy for actuation. Preferably the sleeve and resilient memberare attached at a position spaced apart from the cover axis.

Alternatively to the extensible resilient member, the resilient membermay be compressible to store energy in compression. The energy storagearrangement may comprise a spring abutment which is axially moveablerelative to the sleeve to compress the resilient member to store energy.

Preferably the cover is configured to drive the energy storagearrangement at two opposed positions of the energy storage arrangement.This provides a balanced axial force on the spring.

According to an embodiment of the invention there is provided an inhalercomprising:

a first housing part;

a patient port; and,

a cover mounted to the first housing part via a mating formation so asto be rotatable about a cover axis within an operational range ofmovement between a closed position in which the cover covers the patientport, and an open position in which the patient port is accessible; and,

in which:

the mating formation is configured so as to permit assembly of thehousing part and cover in at least one predetermined rotational positionof the cover which is outside the operational range of movement; and,

the cover is blocked from entering the predetermined rotational positionor range of positions by a further component of the inhaler.

Advantageously, this prevents a user from accidentally or intentionallyremoving the cover which may impair operation of the inhaler.

Preferably the further component is a second housing part, in which thefirst housing part and the second housing part define a volume forreceiving a pMDI canister. Preferably the further component comprisesthe patient port.

Preferably the mating formation comprises:

a first side having an opening; and,

a second side having a projecting shaft configured to engage the openingand rotate therein;

in which the opening and the shaft are shaped such that passage of theshaft into the opening is only possible in the at least onepredetermined rotational position of the cover.

More preferably the opening and shaft define at least one projectingportion, in which the projecting portion of the shaft can pass throughthe projecting portion of the opening in the at least one predeterminedposition, and in which the projecting portion of the shaft acts toretain the cover against a surface of the first housing part in theoperational range of movement.

Preferably the opening and shaft define at least two projectingportions.

The mating formation may comprise:

a first side having an opening defining an inwardly projecting retainingformation; and,

a second side having a projecting shaft with a recess for receiving theretaining formation;

in which the retaining formation and recess are only engageable toenable the first and second sides to mate in the at least onepredetermined position.

The first side may be defined on the first housing part, and the secondside on the cover.

Preferably the cover comprises two arms for mounting to opposite sidesof the first housing part, in which the arms are resiliently deformableaway from each other to enable assembly.

Preferably there is provided:

a resilient structure within the housing defining a void for receiving amedicament-containing canister;

in which the cover is configured to drive the resilient structure tostore energy therein upon rotation from the closed position towards theopen position.

According to an embodiment of the invention there is provided an inhalercomprising:

a housing having a patient port and a cover rotatable about a cover axisbetween a closed position in which the cover covers the patient port,and an open position in which the patient port is accessible;

an extensible resilient structure within the housing defining a void forreceiving a pMDI canister;

in which the cover is configured to drive the resilient structure intension to store energy therein upon rotation from the closed positiontowards the open position.

Advantageously, the providing of a spring under tension reduces anytendency for the spring to deform laterally (i.e. buckle) in use.

Preferably a cam is provided between the cover and the resilientstructure so as to produce a linear force on the resilient structureupon rotation of the cover (i.e. the force does not change direction asthe cover rotates). This provides a mechanically simple and reliablemeans to tension the resilient structure.

Preferably the cam comprises a cam member driven by the cover, the cammember being offset from the cover axis, in which the cam member isengaged with a receiving formation connected to the resilient structure.

Preferably there is provided a sleeve arranged to transfer force fromthe cover to the resilient structure, in which the sleeve surrounds atleast part of the resilient structure, which sleeve is connected to theresilient structure at a position spaced apart from the cover axis.

Preferably the receiving formation is provided on the sleeve.

Preferably the resilient structure comprises a first end configured toapply a compressive force to a canister disposed in the void, and asecond end spaced apart from the first end, in which the sleeve isconnected to the second end.

Preferably there is provided a pMDI canister disposed in the void, thecanister comprising a container and a valve member, in which the secondend of the resilient structure is disposed nearer to the valve memberthan the first end.

Preferably the cam comprises a cam shaft driven by the cover, the camshaft comprising a receiving formation, which receiving formation isengaged by a driven member connected to the resilient structure.

Preferably the cover is configured to drive the resilient structure attwo opposed positions of the resilient structure.

Preferably the resilient structure is a spring which comprises acylindrical body having a plurality of openings defined therein.

Preferably the plurality of openings are arranged in a plurality ofoffset rows. The openings may be circumferentially extending elongateslots.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side section view of a prior art pressurized metered doseinhaler (pMDI);

FIG. 2 is a perspective view of a first priming and reset mechanism of apMDI in accordance with an embodiment of the present invention in afirst (rest) condition;

FIG. 3 is an exploded view of the priming and reset mechanism of FIG. 2;

FIG. 4 is a perspective view of an actuator ring of the priming andreset mechanism of FIG. 2;

FIG. 5 is a perspective view of a cylinder of the priming and resetmechanism of FIG. 2;

FIG. 5a is a detail section view of a part of the cylinder of FIG. 5;

FIGS. 6a to 6c are perspective views of a piston of the priming andreset mechanism of FIG. 2;

FIG. 7 is a perspective view of an o-ring of the priming and resetmechanism of FIG. 2;

FIGS. 8a and 8b are perspective views of a collar of the priming andreset mechanism of FIG. 2;

FIG. 9 is a perspective view of a transfer of the priming and resetmechanism of FIG. 2;

FIG. 10 is a perspective view of a spring of the priming and resetmechanism of FIG. 2;

FIGS. 11a and 11b are perspective views of an actuator body of thepriming and reset mechanism of FIG. 2;

FIGS. 12a and 12b are perspective and section views respectively of amouthpiece cover of the priming and reset mechanism of FIG. 2;

FIGS. 13a to 13c are section views of various parts of the priming andreset mechanism of FIG. 2 in a rest condition;

FIGS. 13d to 13g are side and side section views of stages of assemblyof part of the priming and reset mechanism of FIG. 2;

FIGS. 14a to 14c are section views of various parts of the priming andreset mechanism of FIG. 2 in a primed condition;

FIGS. 14d to 14i are side and side section views of stages of motion ofpart of the priming and reset mechanism of FIG. 2 as it is moved to theprimed condition;

FIGS. 15a and 15b are section views of various parts of the priming andreset mechanism of FIG. 2 in a fired condition;

FIGS. 16a to 16c are views of various parts of the priming and resetmechanism of FIG. 2 in an auto-release condition;

FIGS. 17a to 17b are section views of various parts of the priming andreset mechanism of FIG. 2 in a can reset condition;

FIGS. 18a to 18b are views of various parts of the priming and resetmechanism of FIG. 2 in a return to its rest condition;

FIG. 19 is a perspective view of a pMDI comprising a second priming andreset mechanism in accordance with an embodiment of the presentinvention;

FIG. 20 is an exploded view of the priming and reset mechanism of FIG.19;

FIGS. 21a and b are perspective views of an actuator ring of the primingand reset mechanism of FIG. 19;

FIG. 22 is a perspective view of a cylinder of the priming and resetmechanism of FIG. 19;

FIGS. 23a and 23b are perspective views of a piston of the priming andreset mechanism of FIG. 19;

FIG. 24 is a perspective view of an o-ring of the priming and resetmechanism of FIG. 19;

FIG. 25 is a perspective view of a collar of the priming and resetmechanism of FIG. 19;

FIG. 26 is a perspective view of a transfer of the priming and resetmechanism of FIG. 19;

FIG. 27 is a perspective view of a spring of the priming and resetmechanism of FIG. 19;

FIGS. 28a and 28b are perspective views of an actuator body of thepriming and reset mechanism of FIG. 19;

FIG. 29 is a perspective view of a mouthpiece cover of the priming andreset mechanism of FIG. 19;

FIGS. 30a and 30b are perspective views of a spring sleeve of thepriming and reset mechanism of FIG. 19;

FIGS. 31a to 31d are perspective and section views of various componentsof the priming and reset mechanism of FIG. 19 in a rest condition;

FIGS. 31e to 31g are side and perspective views of stages of assembly ofpart of the priming and reset mechanism of FIG. 19;

FIGS. 32a to 32d are perspective and section views of various parts ofthe priming and reset mechanism of FIG. 19 in a primed condition;

FIGS. 32e to 32g are section views of stages of motion of part of thepriming and reset mechanism of FIG. 19 as it is moved to the primedcondition;

FIG. 33 is a perspective section view of various parts of the primingand reset mechanism of FIG. 19 in a fired condition;

FIG. 34 is a perspective section view of various parts of the primingand reset mechanism of FIG. 19 in an auto-release condition;

FIG. 35 is a perspective view of a pMDI comprising a third priming andreset mechanism in accordance with an embodiment of the presentinvention;

FIG. 36 is an exploded view of the priming and reset mechanism of FIG.35;

FIG. 37 is a perspective view of an actuator ring of the priming andreset mechanism of FIG. 35;

FIG. 38 is a perspective view of a cylinder of the priming and resetmechanism of FIG. 35;

FIGS. 39a and 39b are perspective views of a piston of the priming andreset mechanism of FIG. 35;

FIG. 40 is a perspective view of an o-ring of the priming and resetmechanism of FIG. 35;

FIGS. 41a and 41b are perspective views of a transfer collar of thepriming and reset mechanism of FIG. 35;

FIGS. 42a and 42b are perspective views of a sleeve of the priming andreset mechanism of FIG. 35;

FIGS. 43a and 43b are perspective views of a spring abutment of thepriming and reset mechanism of FIG. 35;

FIG. 44 is a perspective view of a spring of the priming and resetmechanism of FIG. 35;

FIGS. 45a and 45b are perspective views of an actuator body of thepriming and reset mechanism of FIG. 35;

FIG. 46 is a perspective view of a mouthpiece cover of the priming andreset mechanism of FIG. 35;

FIG. 47a is a section view of the priming and reset mechanism of FIG. 35in a rest condition;

FIGS. 47b to 47d are various perspective views of components of thepriming and reset mechanism of FIG. 35 in a rest condition;

FIG. 48a is a perspective view of the pMDI of FIG. 35 in a primedcondition;

FIGS. 48b and 48c are section views of the priming and reset mechanismof FIG. 35 in a primed condition;

FIG. 49 is a section view of the priming and reset mechanism of FIG. 35in a fired condition;

FIG. 50 is a section view of the priming and reset mechanism of FIG. 35in an auto-release condition;

FIG. 51 is a perspective view of a pMDI comprising a fourth priming andreset mechanism in accordance with and embodiment of the presentinvention;

FIG. 52 is an exploded view of the priming and reset mechanism of FIG.51;

FIG. 53 is a perspective view of a cylinder of the priming and resetmechanism of FIG. 51;

FIG. 54 is a perspective view of an o-ring of the priming and resetmechanism of FIG. 51;

FIGS. 55a and 55b are perspective views of a piston of the priming andreset mechanism of FIG. 51;

FIGS. 56a to 56c are perspective views of a transfer collar of thepriming and reset mechanism of FIG. 51;

FIG. 57 is a perspective view of a spring of the priming and resetmechanism of FIG. 51;

FIGS. 58a and 58b are perspective views of an actuator body of thepriming and reset mechanism of FIG. 51;

FIG. 59 is a perspective view of a mouthpiece cover of the priming andreset mechanism of FIG. 51;

FIG. 60a is a section view of the priming and reset mechanism of FIG. 51in a rest condition;

FIG. 60b is a section view through line B of FIG. 60a in a restcondition;

FIG. 60c is a perspective view of a subassembly of the priming and resetmechanism of FIG. 51 in a rest condition;

FIG. 61 is a section view of the priming and reset mechanism of FIG. 51in a primed condition;

FIG. 62a is a section view the priming and reset mechanism of FIG. 51 inan auto-release condition;

FIG. 62b is a perspective view of a subassembly of the priming and resetmechanism of FIG. 51 in an auto-release condition;

FIG. 63 is a section view of the priming and reset mechanism of FIG. 51in a can reset condition; and,

FIG. 64 is a section view of the priming and reset mechanism of FIG. 51in a return to reset condition.

DETAILED DESCRIPTION

FIG. 1 illustrates a conventional pressurized metered dose inhaler(pMDI) 50 comprising a valved container in the form of a canister 51containing a medicament formulation 52, the canister comprising a can 53sealed at a crimp 46 with a metering valve 54. The canister 51 sitswithin a housing (or “actuator”) 55 comprising a tubular sleeve portion56 having an open end 47 dimensioned to receive the canister 51 and fromwhich its base 49 can protrude, and a portion in the form of a patientport 57 (e.g., in the form of a mouthpiece) that defines an inspirationorifice (or an air outlet) 45. Such a patient port of an inhaler issometimes referred to herein as a “mouthpiece” for simplicity. However,it should be understood that such mouthpieces can instead be configuredto be nosepieces of nasal inhalers and that the present disclosure canequally apply to nasal inhalers even where not specifically mentionedherein. The open upper end 47 of the housing 55 can define an aspirationorifice, or an air inlet, and the air outlet 45 can define an inhalationorifice, or an air outlet.

A stem portion 58 protrudes from the metering valve 54 and is locatedand retained by friction in a stem socket 59 formed as an integral partof the housing 55. A spray orifice 60 is formed in the stem socket 59,and provides a passage for fluid communication between the valve stemportion 58 and the inspiration orifice 45. In use, a patient places thepatient port (e.g., mouthpiece) 57 into a body cavity (e.g., mouth) andthen inhales through it while at the same time pressing downwards on theprotruding base 49 of the canister 51. The pressing force serves to movethe canister 51 downwards relative to the valve's stem portion 58. Thatrelative movement serves to isolate a metered dose of medicamentformulation from the bulk formulation in the canister 51 and then todischarge it via a hollow bore 48 formed in the stem portion 58. Thedischarged dose then passes along the fluid passageway through the stemsocket 59 and emerges via a spray orifice in the form of a finerespirable spray 61 that passes through the patient port 57 into thepatient's body cavity (e.g., oral cavity and/or nasal cavity) and thenceinto their respiratory passages, thereby treating their disease.

One important aspect of such a conventional pMDI device 50 that has thepotential to limit its efficacy is, in particular, its need for goodpatient coordination between the timing of the start of inhalation andthe moment at which the canister 51 is pressed downwards. This is achallenge for a high proportion of patients, leading to poor and oftenhighly varying efficacy of medicament administration.

The First Embodiment

Turning to FIGS. 2 to 18 b, part of a first pMDI 150 according to anembodiment of the present invention is shown. The pMDI 150 comprises ahousing or actuator 155 containing a canister (omitted for clarity). Thecanister contains a medicament formulation. It will be understood thatthe canister is of the same type as the canister 51 described withreference to FIG. 1 and comprises a can with a metering valve. Thecanister sits within the housing 155.

The housing 155 comprises a lower section 200 having a tubular sleeveportion 156 dimensioned to receive the canister, and a portion in theform of a patient port 157 (e.g., in the form of a mouthpiece) thatdefines an inspiration orifice (or an air outlet). Such a patient portof an inhaler is sometimes referred to herein as a “mouthpiece” forsimplicity. However, it should be understood that such mouthpieces caninstead be configured to be nosepieces of nasal inhalers and that thepresent disclosure can equally apply to nasal inhalers even where notspecifically mentioned herein.

The housing 155 also comprises an upper section 202 which comprises thereset mechanism according to an embodiment of the present invention.

Referring to FIG. 3, an exploded view of the upper section 202 isprovided. The upper section comprises an actuator ring 204, a cylinder206, a piston 208, a collar 210, a transfer 212, a spring 214, anactuator body 216, an o-ring 218 and a mouthpiece cover 220.

With reference to FIG. 4, the actuator ring 204 is a unitary cylindricalbody constructed from a moulded plastics material having a first, upper,edge 222 and a second, lower, edge 224. The first edge 222 defines threeequally spaced alignment grooves 226 in the form of axially extendingnotches. Each groove has two opposing chamfered regions at the edge 222forming a tapered mouth. The second edge 224 defines a series of fifteenaxially extending teeth 228. Each tooth 228 is generally triangular inshape, having a straight axial edge 230 and a tapered edge 232(extending both axially and circumferentially) which meet at end flat234. Each tooth 228 is separated at the edge 224 by an inter-tooth gap236.

With reference to FIG. 5, the cylinder 206 is a unitary cylindrical bodyconstructed from a moulded plastics material. The cylinder is closed ata first, upper, end 238 and open at a second, lower, edge 241. In thecentre of the upper closed end 238 there is provided a co-axial air leakhole 240. The air leak hole 240 is sized to provide the technical effectdescribed below (damping) and as such the exact size can be determinedby the skilled technician. Referring to FIG. 5a , a detail section viewof the air leak hole 240 is shown. The hole 240 is tapered to decreasein area from the interior of the cylinder 206 to the exterior of thecylinder 206. This results in a higher coefficient of discharge forfluid exiting the cylinder through the hole 240 than air entering thecylinder through the hole 240. As such, the volumetric flow rate ishigher for air exiting the hole 240 than air entering the hole 240 (forthe same pressure difference). To put it another way, more resistance isencountered when separating the piston and cylinder than when engagingthem.

With reference to FIGS. 6a to 6c , the piston 208 is shown. The piston208 is a unitary moulded plastics component. The piston 208 comprises agenerally cylindrical piston body 242 and a piston head 244 at one endthereof.

The body 242 is a hollow cylinder having a first, upper, end 246 atwhich the piston head 244 is located, and a second, lower end 248 whichis open. The body 242 defines fifteen identical, equally spaced, axiallyextending teeth 250 on its outer surface. Each tooth 250 extends fromthe first end 246 towards the second end 248 (although the teeth onlyextend part-way along the body 242). The teeth 250 each terminate at afree end which defines a tapered surface 252 extending bothcircumferentially and axially. The free end also defines a smallcircumferentially extending flat 254 adjacent the tapered surface 252.

The piston head 244 comprises a circular piston end cap 256 having aradial edge 258. The end cap 256 is positioned at the first, upper, end246 of the body 242. The head 244 comprises an o-ring receiving channelsection 260 extending axially towards the second end 248 of the body242. The o-ring receiving channel section 260 is formed by the radialedge 258 of the cap 256 and a radial edge 262 of an annular ring section264. On the underside of the end cap 256 (i.e. the surface facing theinterior of the body 242) there are provided three equally spaced,radially extending stiffening ribs 266. It will be noted from FIGS. 6band 6c in particular that the piston head 244 overhangs the body 242 toprovide an annular recess 268 into which the teeth 250 extend.

Turning to FIG. 7, the o-ring 218 is shown. The o-ring 218 is a standardcomponent and is constructed from an elastomeric material designed toform a fluid seal against plastics material.

Referring to FIGS. 8a and 8b , the collar 210 is shown. The collar 210is a unitary moulded plastics component. The collar 218 comprises acentral cylindrical shaft 270 and an outer annulus 272.

The shaft 270 has a first, upper, end 274 and a second, lower, end 276.The shaft also defines a radially inwardly facing inner surface 278 onwhich a series of fifteen equally spaced inner collar teeth 280 aredefined. Each inner collar tooth 280 is axially extending and defines(i) a tapered first, upper, end 282 and (ii) a tapered, second, lowerend 284. The ends 282, 284 are oppositely tapered giving the teeth 280an elongate trapezium shape. The sides of the teeth 280 are flat andaxially extending. The teeth 280 extend the full axial length of theshaft 270.

The annulus 272 extends outwardly from the shaft 270 midway between theends 274, 276. The annulus 272 comprises a first, upper surface 286 anda second, lower surface 288. The annulus 272 defines an outer rim 290.At the outer rim 290 there are positioned fifteen outer collar teeth292. Each collar tooth 292 extends from the first surface 286 of theannulus 272 in an axial sense. Each outer collar tooth 292 is taperedbecoming narrower as it extends from the first surface 286. Each tooth292 defines a tapered or ramped surface 294 and a flat, axial surface296 which meet at an end flat 298.

Referring to FIG. 9, the transfer 212 is shown in detail. The transfer212 is a unitary, moulded, plastics component comprising an annular body300 and three equally spaced, axially extending legs 302 extendingtherefrom. The annular body 300 comprises a first, upper, surface 304and a second, lower, surface 306 as well as an inner rim 308 and outerrim 310. The upper surface 304 defines an annular bearing surface 316proximate the inner rim 308. The annular bearing surface 316 is slightlyupstanding from the surface 304. Each leg 302 extends from the secondsurface 306 and is circle-segment in section, thus forming apart-cylinder. Each leg 302 has a free end 312 and a rib 314 extendingin an axial direction along its length from the annular body 300 to thefree end 312. Each rib 314 is disposed along the centreline of the innersurface of each leg 302. As such, the ribs 314 face inwardly towardseach other.

Referring to FIG. 10 the spring 214 is shown in detail. The spring 214is a unitary, moulded, plastics component. The spring 214 comprises acylindrical spring body 318 and a spring shaft 320 projecting therefrom.The spring 214 acts as a unitary energy storage arrangement.

The spring body 318 is generally tubular and cylindrical, acting as asleeve for the canister 51. The body 318 has a first, upper, end 322 anda second, lower, end 324. The spring body 318 has a first, upper, region326 and a second, lower region 328.

The first region 326 is axially extensible and resilient. This isachieved by forming a series of six rows of slot-like openings 330through the wall of the body 318. Each row comprises three openings 330which are equally spaced around the circumference of the body 318. Eachrow is rotationally offset from the adjacent row or rows. The openings330 are formed such that the first region 326 can be elasticallyextended, and will resile back to a rest condition as shown in FIG. 10.The second region 328 comprises a first, second and third pair ofoutwardly extending, diametrically opposed pegs 332, 334, 336respectively. The pegs 332, 334 336 are cylindrical. The first peg ispositioned adjacent the first region 326, and the second and third pegsare positioned proximate the second end 324. The second and third pegs334, 336 are closer together than the first and second pegs 332, 334.

The first end 322 of the body 318 terminates in an annular surface 338which defines three leg openings 340 and a series of fifteen springteeth 342. Each leg opening 340 is shaped as a circle-segment. A ribreceiving formation 345 extends in a radially inward direction from thecentre of each leg opening. Thus each leg opening 340 is approximately“T” shaped. The spring teeth 342 are positioned radially inwardly of theleg openings 340. Each spring tooth 342 is generally tapered andcomprises a tapered surface 344 which meets a flat axial surface 346 ata small flat 348.

The spring shaft 320 extends from the centre of the annular surface 338and is constructed as a hollow cylinder. The spring shaft 320 has afirst, upper end 350 and a second, lower, end 352 where it joins theannular surface 338. The spring shaft 320 has three equally spacedspring alignment grooves 354 which extend axially from the first end350.

Referring to FIGS. 11a and 11b , the actuator body 216 is shown indetail. FIG. 11b is in cross-section through plane B in FIG. 11a . Theactuator body 216 comprises a first, upper, section 356 and a second,lower, section 358. The sections 356, 358 define a generally elongatehousing enclosing a cavity which is open at the lower end.

The first section 356 is generally cylindrical having a first, upper endwhich is closed by an endwall 360. Three equally spaced actuator ringribs 361 are provided extending axially from the endwall 360 along thesidewalls.

The second section 358 is generally rectangular in cross-section andjoins the first section 356 via a pair of shoulders 364. The secondsection 358 has an open end 366. A pair of diametrically opposedcircular apertures 368 are disposed in opposing walls of the secondsection proximate the shoulders 364. Each aperture 368 defines aretaining flange 370 projecting radially inwardly though a portion ofits circumference. Both apertures lie on a mouthpiece cover axis M.Extending from each aperture 368 along the respective interior sidewallof the second section 358 there is provided a spring peg groove 372. Thespring peg grooves 372 start from a position substantially opposite theretaining flange 370 and extend axially within the second section 358 tothe open end 366.

Referring to FIGS. 12a and 12b , the mouthpiece cover 220 is shown inmore detail. The mouthpiece cover 220 is a unitary, moulded plasticscomponent. FIG. 12b is in cross-section through plane B in FIG. 12a .The mouthpiece cover 220 comprises a cap 374 and two arms 376 that aremirror images of each other.

The cap 374 is an internally concave structure suitable for sealing amouthpiece of the inhaler patient port 157. The cap 374 has a closed end378 and an open end 380. The cap 374 defines a pair of opposed sidewalls382 from which the arms 376 extend proximate the open end 380.

Each arm 376 is an elongate, generally planar structure extending to afree end 384. At the free end, and on an inwardly facing surface of eacharm 376 there is provided a cam 386. The cam 386 is connected to the arm376 via an undercut region 388 (it will be understood that the term“undercut” is used in the geometric sense, and does not imply that acutting operation has taken place).

The cam 386, with reference to FIG. 12b has an outer radius Ro and apeg-receiving notch 390 which extends inwardly of Ro to an inner radiusRi. The notch 390 has a first, shallow surface 392 which curves gentlybetween Ro and Ri and a second surface 394 which extends more steeplybetween Ro and Ri (almost radially).

Assembly

All of the components described above are aligned on a main axis X.Referring to FIGS. 13a to 13c (as well as the exploded view of FIG. 3),the upper section 202 is shown in its assembled state, in a restcondition (used for storage and generally when not in operation).

The actuator ring 204 is secured to the inside of the actuator body 216by inserting it into the first section 356 such that the actuator ringribs 361 engage the alignment grooves 226. The tapered mouths of thealignment grooves 226 aid this mating process. Once inserted, theactuator ring 204 is held such that it cannot move relative to theactuator body 216. For example, it may be bonded thereto.

The o-ring 218 is assembled into the groove 260 on the piston 208, andthe piston 208 is inserted into the open end of the cylinder 206 to forma seal therewith. The o-ring 218 seals against the inner sidewall of thecylinder 206 such that axial movement of the piston results in airflowthrough the air leak hole 240. As such, relative motion of the piston208 and the cylinder 206 is damped. Further, because the hole 240 istapered, movement of the piston 208 into the cylinder 206 is resistedless than movement of the piston 208 out of the cylinder 206. In otherwords, separation of the piston 208 and cylinder 206 is damped more thanmovement of the piston 208 into the cylinder 206.

The piston-cylinder assembly is positioned within the actuator ring 204and can move axially relative thereto.

Next, the collar 210 is placed into the actuator body 216 such that theouter collar teeth 292 face the actuator ring teeth 228 and areinterspersed therebetween. The collar surrounds the piston body 242. Theupper surfaces 282 of the inner collar teeth 280 face the downwardlyfacing surfaces 252 of the piston teeth 250.

Next, the transfer 212 is inserted into the actuator body 216 to engagethe underside of the collar 210. The transfer bearing surface 316 bearsagainst the lower surface 288 of the collar annulus 272 and can rotaterelative thereto.

Finally, the spring 214 is inserted into the actuator body 216 such thatthe spring shaft 320 passes into the piston 208. The three alignmentgrooves 354 are engaged by the ribs 266 and the spring 214 and piston208 are bonded to prevent relative motion (save for that resulting fromdeformation of the spring). The legs of the transfer 212 pass throughthe leg openings 340 in the spring body 318 to allow relative axialmovement, but not relative rotational movement between the spring 214and transfer 212. The spring teeth 342 face the downwardly facingsurfaces 284 of the teeth 280 of the collar 210.

As the spring 214 is inserted, the pegs 332, 334, 336 engage the springpeg grooves 372 (FIG. 13b ). The first peg 332 is engaged by the notch390 of the mouthpiece cover 220 which is snap-fitted to the actuatorbody 216 in the following manner.

Referring to FIGS. 13d to 13g , the installation of the mouthpiece cover220 on the actuator body 216 is shown in detail. In order to do thisinstallation, the lower section 200 including the patient port 157 musthave not yet been assembled onto the actuator body 216. In FIGS. 13d and13e the intended location of the lower section 200 is shown in dashedoutline. The mouthpiece cover 220 has a rest position defining an axis Ywhich is parallel to the main axis X of the inhaler. In the restposition, the mouthpiece cover 220 covers the inhaler mouthpiece (seeFIG. 2).

In FIGS. 13d and 13e , the arms 376 of the mouthpiece cover 220 areresiliently separated such that the cams 386 can be aligned with theopenings 368 in the actuator body 216. The cams 386 enter the openings368 such that the arms 376 of the mouthpiece cover 220 are in slidingcontact with the flat walls of the second section 358 of the actuatorbody 216. It will be noted that in order for full engagement of the cams386 with the openings 368, the notch 390 needs to be aligned with theretaining flange 370. This only occurs at one specific rotationalassembly angle AA of the mouthpiece cover 220, specifically atapproximately −110 degrees about the mouthpiece cover axis M.

The mouthpiece cover 220 is rotated to the rest position (in which thecap 374 covers the mouthpiece of the pMDI 150). This is shown in FIGS.13f and 13g . In this position, the retaining flange 370 is engaged withthe undercut region 388 of the cam 386 on the mouthpiece cover 220 tohold the mouthpiece in position (but allow rotation about the axis M).As shown in FIGS. 13b and 13g , the first peg 332 of the spring 214 iscaptured by the notch 390 in the cam 386 of the mouthpiece cover 220. Itwill be noted that upon assembly of the lower section 200 including thepatient port 157 onto the actuator body 216, the mouthpiece cover is nolonger able to rotate towards the assembly position of FIGS. 13d and 13e. This ensures that once the inhaler is fully assembled, it is verydifficult to remove the mouthpiece cover.

Operation

The pMDI 150 is used as follows. The operation of the pMDI 150 is bestdescribed as passing through a number of operational conditions orstages as will be described below.

1. Rest Condition

The rest condition is shown in FIGS. 13a to 13c . In this condition, acanister 51 having a can 53 and a metering valve 54 with a valve stem 58is provided within the pMDI. The canister 51 is shown in hidden line forclarity. The stem 58 abuts a stem abutment 59 which is static within thepMDI 150. In the rest condition, downward travel of the canister 51 isinhibited by a trigger abutment 70 which is part of a trigger assembly(not described here, but generally known in the art).

In this position, the canister 51 is positioned partly within the spring214, and the free ends 312 of the legs 302 of the transfer 212 abut thebottom of the canister 51 (as it is inverted). The transfer 212 supportsthe collar 210 whose outer collar teeth 292 are interdigitated with thedownwardly projecting teeth 228 of the actuator ring 204. The straightedges 230, 296 of each respective tooth 228, 292 abut such that rotationof the collar 210 in a first rotational direction +R about axis X isprevented.

The spring 214 is also in a rest position, and stores no energy. Becauseit is fixed at its lower end, (with its first pef 332 held in the notch390 of the mouthpiece cover 220) and is attached to the piston 208 italso supports the cylinder 206. The piston 208 and cylinder 206 arefully engaged with the piston abutting the base of the cylinder as shownin FIG. 13c . The piston teeth 250 are spaced apart along axis X fromthe inner collar teeth 280.

The annular surface 338 of the spring 214 is abutted by the lower endsof the inner collar teeth 280, such that they are interdigitated withthe spring teeth 342.

2. Primed Condition

In this condition, the mouthpiece cover 220 has been rotated about themouthpiece cover axis M, such that (with reference to FIG. 13b ) thefirst peg 332 has been drawn into the spring peg groove 372. This actiontends to apply a tensile force to the first region of the spring 326,drawing it downwards.

Various steps in the motion of the mouthpiece cover moving from the restto the primed condition are shown in FIGS. 14d to 14 i.

FIGS. 14d and 14e show the mouthpiece cover 220 at an angle A of 90degrees to the axis Y. As visible in FIG. 14e , rotation of the cam 386has urged the peg 332 almost fully into the groove 372. The peg 332 hasbeen displaced from the rest position (shown in hidden line) by D1. Atthis position, the inhaler is unusable because the mouthpiece cover 220would clash with the user's face if they tried to place their mouth overthe mouthpiece.

FIGS. 14f and 14g show the position of the mouthpiece cover at an angleB of approximately 135 degrees when the cam 386 has rotated to an extentthat the peg 332 is almost fully within the groove 372 and has moved bya total distance of D2. At this point, because the notch 390 has clearedthe peg 332, further rotation of the mouthpiece cover 220 has no effecton the linear position of the peg 332 (which remains at D2). At thisposition it is still not possible to use the inhaler because themouthpiece cover is still in a position where it would clash with theuser's face.

FIGS. 14h and 14i show the final, primed position of the mouthpiececover at an angle C of 180 degrees. Movement from angle B to C did notcause any further movement of the peg 332 (and therefore no furthercompression of the spring 214), but served to move the mouthpiece 220out of the way. This lost motion ensures that should a user attempt touse the inhaler between positions B and C (which may be possible), theinhaler will operate as normal because the spring 214 is fullyenergised.

Referring back to FIG. 14a , initially this downward force on the spring214 acts to draw the piston 208 downwards (the piston 208 and spring 214are attached). Because downward movement of the cylinder 206 is notresisted at this stage, it also moves downwards as shown in FIG. 14a dueto gravity and the friction of the o-ring 218, as well as due to airflow resistance through the air hole. The transfer 212 remainsstationary at this point, as it abuts the canister 51. As the top of thespring 214 moves downwards along axis X, the spring 214 and the transfer212 start to move apart due to the fact that the transfer legs 302 canslide in the leg openings 340.

This initial motion occurs until, as shown in FIG. 14c , the taperedsurfaces 252 of the piston teeth 250 abut the first tapered ends 282 ofthe inner collar teeth 280. At this point, a downward force is exertedon the collar 210 which cannot move due to the abutment of the transfer212 and the canister 51 (held in place by the trigger abutment 70).Therefore the spring shaft 320 can no longer move due a load pathestablished through the piston 208 onto the collar 210, the transfer 212and the canister 51. As the mouthpiece cover 220 continues to berotated, the first region of the spring 326 stretches to store potentialenergy. Once the mouthpiece cover 220 is in the position shown in FIG.14a , the first peg 332 of the spring 214 has moved down into the pegchannel 372 and the spring is “primed”.

It will be noted that the abutment of the piston 208 (and morespecifically the piston teeth 250) and the collar 210 (and morespecifically the inner collar teeth 280) forms a clutch in the load pathbetween the spring 214 and the canister 51.

3. Fired Condition

When the user wishes to dispense the medicament, a trigger mechanism(which is not described here) is fired in which the trigger abutment 70is moved such that downward motion of the canister 51 is no longerinhibited. Release of the canister 51 releases the transfer 212, collar210 and piston 208 to move downwards, pulled by the tensile force of thespring 214 on the piston 208. As the stored energy in the spring 214 isreleased, it serves to push the valve stem 58 onto the valve stemabutment 59. This also acts against the bias of the valve spring withinthe valve 54 to open the canister 51 and release a dose of medicament.Because the force from the spring 214, Fs, exceeds that from the valve54, Fv, at this juncture, dose release is ensured.

It will also be noted, with reference to FIG. 15b , that force from thepiston 208 onto the collar 210 is provided via the tapered surfaces 252of the piston teeth 250 abutting the first tapered ends 282 of the innercollar teeth 280. In other words, the load path of the spring force Fsis through the clutch formed by the piston 208 (being pulled down by thespring) and the collar 210 (pushing on the transfer 212).

Due to the taper of the piston teeth 250 and the inner collar teeth 280,as well as an axial force, a rotational force on the collar 210 indirection+R about the axis X is produced. This force is reacted byabutment of the axial surfaces 296 of the outer collar teeth 292 and theaxial surfaces 230 of the downwardly projecting teeth 228 of theactuator ring 204. It will be understood that FIG. 15b shows that theteeth 292, 228 have just cleared each other due to relative downwardmotion of the collar 210 relative to the actuator ring 204. Until theyhave done so, rotation of the collar is prevented.

4. Auto-Release Condition

As shown in FIG. 15b , the outer collar teeth 292 eventually clear theactuator ring teeth 228 and allow the collar 210 to rotate about theaxis X in direction+R (FIG. 16b ). This rotation occurs due to thetorque created by the abutment of the tapered surfaces 252 of the pistonteeth 250 abutting the first tapered ends 282 of the inner collar teeth280 (FIG. 16c ).

At a predetermined angle of rotation of the collar 210 relative to thepiston (which cannot rotate, because it is bonded to the spring, whichitself cannot rotate), the collar 210 and piston become detached (orreleased) in a linear sense. In other words, as the collar 210 rotates,the clutch formed by the collar 210 and piston 208 is released. This isbecause the inner collar teeth 280 can eventually move through the gapsbetween the piston teeth 250 allowing relative linear movement betweenthe piston 208 and collar 210.

5. Can Reset Condition

The release of the clutch now separates the system into twosub-assemblies which encounter opposing forces. Reference is made toFIGS. 17a and 17 b.

On one hand, the return force of the spring in the canister valve Fvapplies an upward force on the transfer (via the canister 51) which inturn lifts the collar 210 towards the actuator ring 204. The collar 210supports the cylinder 206 which is also raised upwards further into theactuator ring. As the collar 210 approaches the actuator ring 204, thetapered surfaces 294 of the outer collar teeth 292 engage the taperedsurfaces 232 of the actuator ring teeth 228 thus rotating the collarfurther in the direction+R about the axis X to fully engage the collar210 and actuator ring 204.

On the other hand, the tensile force Fs remaining in the spring 214 actsto draw the piston 208 downwards. Therefore, as the canister 51 resilesto its rest (unactuated) position, its motion is controlled by theseparation of the piston 208 and cylinder 206. As mentioned above,relative motion of the piston 208 and cylinder 206 is controlled byingress of air into the air leak hole 240. As such, the return of thecanister 51 (i.e. the timing of return of the canister) is controlled,avoiding the aforementioned problems.

6. Return to Rest Condition

The user rotates the mouthpiece cover 220 back to its original position,which has the effect of (with reference to FIG. 13b ) drawing the firstpeg 332 upwards, thereby allowing the first region of the spring 326 toreturn upwards towards its starting (rest) position. This motionre-engages the piston 208 into the cylinder 206, the piston encounteringa lower resistance (i.e. is less damped) than when the piston andcylinder were being separated.

Referring to FIGS. 18a and 18b , as the top of the spring 214 movestowards the collar 210, the tapered surface 344 of each spring tooth 342engages the tapered second end 284 of each inner collar tooth 280 tofurther rotate the collar 210. The rotation is such that the innercollar teeth 280 are positioned directly below the piston teeth 250,ready for the next operation. In other words, the opposite sides of theclutch are re-aligned. This rotation also brings the straight edges 230of the actuator ring teeth 228 into abutment with the straight edges 296of the outer collar teeth 292. As such, further rotation of the collar210 in a first rotational direction+R about axis X (to release theclutch) is again prevented.

The Second Embodiment

Turning to FIGS. 19 to 29, a second pMDI 1150 according to an embodimentof the present invention is shown. The pMDI 1150 comprises a housing oractuator 1155 containing a canister 51 (FIG. 20). The canister 51contains a medicament formulation. It will be understood that thecanister is of the same type as the canister 51 described with referenceto FIG. 1 and comprises a can with a metering valve. The canister sitswithin the housing 1155. The pMDI 1150 has a stem socket and a triggerassembly that allows downward movement of the canister relative to thevalve's stem portion as described earlier in the detailed description,when the patient inhales through the mouthpiece. The stem socket andtrigger assembly have been omitted from FIG. 20 for clarity of thedrawing.

The pMDI 1150 comprises a portion in the form of a patient port 1157(e.g., in the form of a mouthpiece) that defines an inspiration orifice(or an air outlet). Such a patient port of an inhaler is sometimesreferred to herein as a “mouthpiece” for simplicity. However, it shouldbe understood that such mouthpieces can instead be configured to benosepieces of nasal inhalers and that the present disclosure can equallyapply to nasal inhalers even where not specifically mentioned herein.

The housing 1155 also comprises an upper section 1202 that comprises areset mechanism according to an embodiment of the present invention.

Referring to FIG. 20, an exploded view of the reset mechanism isprovided. The reset mechanism comprises an actuator ring 1204, acylinder 1206, a piston 1208, a collar 1210, a transfer 1212, a spring1214, a spring sleeve 1400, a first actuator body part 1216, a secondactuator body part 1217, an o-ring 1218 and a mouthpiece cover 1220.

With reference to FIGS. 21a and b , the actuator ring 1204 is a unitarycylindrical body constructed from a moulded plastics material having afirst, upper, edge 1222 and a second, lower, edge 1224. The first edge1222 defines a series of fifteen axially extending teeth 1228. Eachtooth 1228 is generally triangular in shape, having a straight axialedge 1230 and a tapered surface 1232 (extending both axially andcircumferentially) which meet at end flat 1234. Each tooth 1228 isseparated at the edge 1222 by an inter-tooth gap 1236. The second edge1224 defines an outwardly extending rim 1226. At a first circumferentialposition there is provided an axially extending retention member 1227.On the inner surface of the actuator ring 1204 at the retention member1227 there is provided an axially extending slot 1225.

With reference to FIG. 22, the cylinder 1206 is a unitary cylindricalbody constructed from a moulded plastics material. The cylinder isclosed at a first, upper, end 1238 and open at a second, lower, edge1241. In the centre of the upper closed end 1238 there is provided aco-axial air leak hole 1240. The air leak hole 1240 is sized to providethe technical effect described below (damping) and as such the exactsize can be determined by the skilled technician. As with the air leakhole 240, the air leak hole 1240 is tapered to decrease in area from theinterior of the cylinder 1206 to the exterior of the cylinder 1206. Thisresults in a higher coefficient of discharge for fluid exiting thecylinder through the hole 1240 than air entering the cylinder throughthe hole 1240.

With reference to FIGS. 23a and 23b , the piston 1208 is shown. Thepiston 1208 is a unitary moulded plastics component. The piston 1208comprises a generally cylindrical piston body 1242 and a piston head1244 at one end thereof.

The body 1242 is a hollow cylinder having a first, upper, end 1246 atwhich the piston head 1244 is located, and a second, lower end 1248which is open. The body 1242 defines five identical, equally spaced,axially extending teeth 1250 on its outer surface. Each tooth 1250extends from the first end 1246 towards the second end 1248 (althoughthe teeth only extend part-way along the body 1242). The teeth 1250 eachterminate at a free end which defines a tapered surface 1252 extendingboth circumferentially and axially.

The piston head 1244 comprises a circular piston end cap 1256 having aradial edge 1258. The end cap 1256 is positioned at the first, upper,end 1246 of the body 1242. The head 1244 comprises an o-ring receivingchannel section 1260 extending axially towards the second end 1248 ofthe body 1242. The o-ring receiving channel section 1260 is formed bythe radial edge 1258 of the cap 1256 and a radial edge 1262 of anannular ring section 1264. On the underside of the end cap 1256 (i.e.the surface facing the interior of the body 1242) there are providedthree equally spaced, radially extending ribs 1266 which meet at acentral boss 1267. It will be noted from FIG. 23b in particular that thepiston head 1244 overhangs the body 1242 to provide an annular recess1268 into which the teeth 1250 extend.

Turning to FIG. 24, the o-ring 1218 is shown. The o-ring 1218 is astandard component and is constructed from an elastomeric materialdesigned to form a fluid seal against plastics material.

Referring to FIG. 25, the collar 1210 is shown. The collar 1210 is aunitary moulded plastics component. The collar 1210 comprises a centralcylindrical shaft 1270 and an outer annulus 1272.

The shaft 1270 has a first, upper, end 1274 and a second, lower, end1276. The shaft also defines a radially inwardly facing inner surface1278 on which a series of fifteen equally spaced inner collar teeth 1280are defined. Each inner collar tooth 1280 is axially extending anddefines (i) a tapered first, upper, end 1282 and (ii) a tapered, second,lower end 1284. The ends 1282, 1284 are oppositely tapered giving theteeth 1280 an elongate trapezium shape. The sides of the teeth 1280 areflat and axially extending. The teeth 1280 extend the full axial lengthof the shaft 1270.

The annulus 1272 extends outwardly from the shaft 1270 midway betweenthe ends 1274, 1276. The annulus 1272 comprises a first, upper surface1286 and a second, lower surface 1288. The annulus 1272 defines an outerrim 1290. At the outer rim 1290 there are positioned fifteen outercollar teeth 1292. Each collar tooth 1292 extends radially outwardly andaxially downwards away from the second surface 1288. Each outer collartooth 1292 is tapered becoming narrower as it extends from the secondsurface 1288. Each tooth 1292 defines a tapered or ramped surface 1294and a flat, axial surface 1296 which meet at an end flat 1298.

Referring to FIG. 26, the transfer 1212 is shown in detail. The transfer1212 is a unitary, moulded, plastics component comprising an annularbody 1300 and three equally spaced, axially extending legs 1302extending therefrom. The annular body 1300 comprises a first, upper,surface 1304 and a second, lower, surface 1306 as well as an inner rim1308 and outer rim 1310. The upper surface 1304 defines an annularbearing surface 1316 proximate the inner rim 1308. The annular bearingsurface 1316 is slightly upstanding from the surface 1304. Each leg 1302extends from the second surface 1306 and is circle-segment in section,thus forming a part-cylinder. Each leg 1302 has a free end 1312 and arib 1314 extending in an axial direction along its length from theannular body 1300 to the free end 1312. Each rib 1314 is disposed alongthe centreline of the inner surface of each leg 1302. As such, the ribs1314 face inwardly towards each other.

Referring to FIG. 27 the spring 1214 is shown in detail. The spring 1214is a unitary, moulded, plastics component. The spring 1214 comprises acylindrical spring body 1318 and a spring shaft 1320 projectingtherefrom.

The spring body 1318 is generally cylindrical having a first, upper, end1322 and a second, lower, end 1324. The spring body 1318 has a first,upper, region 1326 and a second, lower region 1328.

The first region 1326 is axially extensible and resilient. This isachieved by forming a series of six rows of slot-like openings 1330through the wall of the body 1318. Each row comprises three openings1330 which are equally spaced around the circumference of the body 1318.Each row is rotationally offset from the adjacent row or rows. Theopenings 1330 are formed such that the first region 1326 can beelastically extended, and will resile back to a rest condition as shownin FIG. 27. The first region 1326 further defines an alignment peg 1332extending radially outwardly therefrom proximate the first, upper end1322.

The second region 1328 comprises two circle segment radially outwardlyprojecting ribs 1334, 1335 proximate the second end 1324. Between theribs 1334, 1335 and the first region 1326 there is provided a radiallyoutwardly projecting tab 1336 which is resiliently biased by anelastically deformable arm 1337 such that upon depression into the body1326 the tab 1336 resiles outwardly back to the position shown in FIG.27.

The first end 1322 of the body 1318 terminates in an annular surface1338 which defines three leg openings 1340 and a series of five springteeth 1342. Each leg opening 1340 is shaped as a circle-segment. A ribreceiving formation 1345 extends in a radially inward direction from thecentre of each leg opening Thus each leg opening 1340 is approximately“T” shaped. The spring teeth 1342 are positioned radially inwardly ofthe leg openings 1340. Each spring tooth 1342 is generally tapered andcomprises a tapered surface 1344 which meets a flat axial surface 1346.

The spring shaft 1320 extends from the centre of the annular surface1338 and is constructed as a hollow cylinder. The spring shaft 1320 hasa first, upper end 1350 and a second, lower, end 1352 where it joins theannular surface 1338. The spring shaft 1320 has three equally spacedspring alignment grooves 1354 which extend axially from the first end1350.

Referring to FIGS. 28a and 28b , the actuator body parts 1216 and 1217are shown in detail in exploded form.

The first actuator body part 1216 is a unitary, moulded plasticscomponent which is generally elongate and concave having a curved wall1402, a first end 1404 and a second end 1406 opposite the first. On theinterior side of the concave wall 1402 there is provided a downwardlyfacing collar abutment 1408 in the form of a shoulder, and an actuatorring abutment 1410 in the form of a circumferentially and radiallyinwardly extending rib, that has a central gap 1412. The wall 1402 alsocomprises two parallel side panels 1414 extending from either sidethereof. Each side panel 1414 is flat and defines an opening 1416therein. Each opening 1416 is generally circular having two opposedwings 1418, 1420 extending tangentially therefrom. The wall 1402 alsodefines four longitudinally extending stiffening ribs 1422. Bothopenings 1416 lie on a mouthpiece cover axis M.

The second actuator body part 1217 is a unitary, moulded plasticscomponent which is generally elongate and concave having a curved wall1424, a first endwall 1426 and a second endwall 1428 opposite the first.On the interior side of the concave wall 1424 there is provided adownwardly facing collar abutment 1430 in the form of a shoulder, and anactuator ring abutment 1432 in the form of a circumferentially andradially inwardly extending rib. The wall 1424 also defines fourlongitudinally extending stiffening ribs 1434.

Referring to FIG. 29, the mouthpiece cover 1220 is shown in more detail.The mouthpiece cover 1220 is a unitary, moulded plastics component. Themouthpiece cover 1220 comprises a cap 1374 and two arms 1376 that aremirror images of each other.

The cap 1374 is an internally concave structure suitable for sealing amouthpiece of the inhaler patient port 1157. The cap 1374 has a closedend 1378 and an open end 1380. The cap 1374 defines a pair of opposedsidewalls 1382 from which the arms 1376 extend proximate the open end1380.

Each arm 1376 is an elongate, generally planar structure extending to afree end 1384. At the free end 1384, and on an inwardly facing surfaceof each arm 1376 there is provided a cam 1386. The cam 1386 comprises agenerally cylindrical body 1388 having two tangentially extending,opposed wings 1436. The cam also defines an inwardly projecting cam lug1438 which is off-centre on the cylindrical body 1388.

Referring to FIGS. 30a and 30b , the spring sleeve 1400 is a unitary,moulded plastics component which is generally cylindrical having a first(upper) end 1440 and a second (lower) end 1442. A rectangular, axiallyextending slot 1444 is provided at one circumferential position on thespring sleeve 1400, the slot 1444 extending from the first end 1440approximately halfway towards the second end 1442. Extending from theslot 1444 to the second end 1442 there is provided an axially extendingridge 1446, which projects radially outwardly from the spring sleeve1400. On the interior side of the ridge 1446 there is provided anaxially extending recess 1448.

Two elongate openings 1450 are provided in the spring sleeve 1400proximate and parallel to the first end 1440. Each opening has a curvedend 1452 and a ramped end 1454. The openings 1450 are at oppositepositions on the spring sleeve 1400 and are mirror images of each other.

At the second end 1442 of the spring sleeve 1400 there are provided twoclips 1456, each of which is generally “L” shaped to form a slot 1458with the second end 1442. The clips 1456 are disposed at oppositecircumferential positions on the second end 1442 and face in the samecircumferential direction.

Assembly

The components described above are aligned on a main axis X. Referringto FIGS. 31a and 31b (as well as the exploded view of FIG. 20), thesystem is shown in its assembled state, in a rest condition (used forstorage and generally when not in operation). The view in FIG. 31a is insection A of FIG. 19. The view in FIG. 31b is in direction B of FIG. 19,but with the first actuator body part 1216 removed.

The o-ring 1218 is assembled into the groove 1260 on the piston 1208,and the piston 1208 is inserted into the open end of the cylinder 1206to form a seal therewith. The o-ring 1218 seals against the innersidewall of the cylinder 1206 such that axial movement of the pistonresults in airflow through the air leak hole 1240. As such, relativemotion of the piston 1208 and the cylinder 1206 is damped. Further,because the hole 1240 is tapered, movement of the piston 1208 into thecylinder 1206 is resisted less than movement of the piston 1208 out ofthe cylinder 1206. In other words, separation of the piston 1208 andcylinder 1206 is damped more than movement of the piston 1208 into thecylinder 1206.

The piston-cylinder assembly is positioned within the actuator bodyparts 1216, 1217 and can move axially relative thereto.

Next, the collar 1210 is placed into the actuator body parts 1216, 1217such that the outer collar teeth 1292 face downwardly as shown in FIG.31b . The upper surface 1286 of the annulus 1272 of the collar 1210abuts the collar abutments 1408, 1430 of the respective actuator bodyparts 1216, 1217. The collar surrounds the piston body 1242. The uppersurfaces 1282 of the inner collar teeth 1280 face the downwardly facingsurfaces 1252 of the piston teeth 1250.

Next, the transfer 1212 is inserted into the actuator body parts 1216,1217 to engage the underside of the collar 1210. The transfer bearingsurface 1316 bears against the lower surface 1288 of the collar annulus1272 and can rotate relative thereto.

The actuator ring 1204 is secured to the inside of the actuator bodyparts 1216 and 1217 and rests on the actuator ring abutments 1410, 1432.Rotation of the ring 1204 is inhibited by capture of the retentionmember 1227 in the central gap 1412 of the actuator ring abutment 1410.Once assembled, the actuator ring 1204 cannot move relative to theactuator body parts 1216, 1217. For example, it may be bonded thereto.As shown in FIG. 31b , the upwardly facing teeth 1228 of the actuatorring 1204 are aligned with the downwardly facing outer teeth 1292 of thecollar 1210.

Referring to FIG. 31c , an energy storage arrangement which is asub-assembly of the spring 1214 and spring sleeve 1400 is shown. Thespring 1214 is inserted into the spring sleeve 1400 from the first end1440 until the clips 1456 pass through the gaps between the ribs 1334,1335. The second end 1442 of the spring sleeve 1400 abuts the ribs 1334,1335. At this point, the tab 1336 (not visible in FIG. 31c ) isdepressed by the interior wall of the spring sleeve 1400. The springsleeve 1400 is then rotated to the position shown in FIG. 31c such thatthe ribs 1334, 1335 enter the slots 1458, and the tab 1336 resilesoutwardly into the recess 1448. In this way, the spring 1214 and springsleeve 1400 are attached at their respective first (lower) ends. It willbe noted that the spring 1214 can still extend.

The spring 1214 and spring sleeve 1400 are inserted into the actuatorbody parts 1216, 1217 such that the spring shaft 1320 passes into thepiston 1208. The three alignment grooves 1354 are engaged by the ribs1266 and the spring 1214 and piston 1208 are bonded to prevent relativemotion (save for that resulting from deformation of the spring). Thelegs of the transfer 1212 pass through the leg openings 1340 in thespring body 1318 to allow relative axial movement, but not relativerotational movement between the spring 1214 and transfer 1212. Thespring teeth 1342 face the downwardly facing surfaces 1284 of five ofthe inner teeth 1280 of the collar 1210.

The alignment peg 1332 of the spring engages the slot 1225 of theactuator ring 1204 such that this part of the spring can slidevertically.

The mouthpiece cover 1220 is snap-fitted onto the first actuator bodypart 1216 in the following manner.

Referring to FIGS. 31e to 31g , the installation of the mouthpiece cover1220 on the first actuator body part 1216 is shown in detail. Themouthpiece cover 1220 has a rest position defining an axis Y which isparallel to the main axis X of the inhaler. In the rest position, themouthpiece cover 1220 covers the inhaler mouthpiece (see FIG. 31g ).

In FIGS. 31e and 31f , the arms 1376 of the mouthpiece cover 1220 areresiliently separated such that the cams 1386 can be aligned with theopenings 1416 in the first actuator body part 1216. The cams 1386 enterthe openings 1416 such that the arms 1376 of the mouthpiece cover 1220are in sliding contact with the walls 1414 of the first actuator bodypart 1216. It will be noted that in order for full engagement of thecams 1386 with the openings 1416, the wings 1436 of the cam 1386 need tobe aligned with the wings 1418, 1420 of the openings 1416. This onlyoccurs at one specific rotational assembly angle AA of the mouthpiececover 1220, specifically at approximately −200 degrees about themouthpiece cover axis M from axis Y (FIG. 31e ). Referring to FIG. 31f ,a detailed view of one of the cams 1386 having entered the opening 1416is shown.

The mouthpiece cover 1220 is rotated to the in the rest position perFIG. 31g (in which the cap 1374 covers the mouthpiece of the pMDI 1150).In this position, the wings 1436 abut the interior side of the firstactuator body part 1416 to hold the mouthpiece in position (but allowrotation about the axis M). It will be noted that upon assembly of thesecond actuator body part 1217, onto the first actuator body part 1216,the mouthpiece cover is no longer able to rotate further than 180degrees towards the assembly position of FIGS. 31e and 31f , because themouthpiece cover 1220 is unable to pass over the top rear edge of thesecond actuator body part 1217. This ensures that once the inhaler isfully assembled, it is very difficult to remove the mouthpiece cover.

The cam lugs 1438 engage the openings 1450 on the spring sleeve 1400(FIG. 31d ).

Operation

The pMDI 1150 is used as follows. The operation of the pMDI 1150 is bestdescribed as passing through a number of operational conditions orstages as will be described below.

1. Rest Condition

The rest condition is shown in FIGS. 31a to 31d . In this condition, acanister 51 having a can 53 and a metering valve 54 with a valve stem 58is provided within the pMDI. The stem 58 abuts a stem abutment which isstatic within the pMDI 1150. In the rest condition, downward travel ofthe canister 51 is inhibited by a trigger abutment which is part of atrigger assembly (not described here, but generally known in the art).

In this position, the canister 51 is positioned partly within the spring1214 (FIG. 31a ), and the free ends 1312 of the legs 1302 of thetransfer 1212 abut the bottom of the canister 51 (as it is inverted).The transfer 1212 supports the collar 1210 whose outer collar teeth 1292are aligned with, and facing, the upwardly projecting teeth 1228 of theactuator ring 1204.

The spring 1214 is also in a rest position, and stores no energy. Thespring is fixed to the spring sleeve 1400, which in turn is supported onthe lugs 1438 of the mouthpiece cover 1220. Because the spring shaft1320 is attached to the piston 1208 it also supports the cylinder 1206.The piston 1208 and cylinder 1206 are fully engaged, with the pistonabutting the base of the cylinder as shown in FIG. 31a . The pistonteeth 1250 are spaced apart along axis X from the inner collar teeth1280.

The annular surface 1338 of the spring 1214 is abutted by the lower endsof the inner collar teeth 1280, such that they are interdigitated withthe spring teeth 1342.

2. Primed Condition

Turning to FIGS. 32a to 32c , the mouthpiece cover 1220 has been rotatedabout the mouthpiece cover axis M, such that (with reference to FIG. 32b) the lug 1438 has moved downwards in the housing. Because the lugs 1438are engaged in the openings 1450 in the spring sleeve, rotation of themouthpiece cover 1220 pushes the spring sleeve 1450 verticallydownwards. This action also applies a tensile force to the spring 1214,pulling it downwards.

Referring to FIGS. 32e to 32g , two intermediate steps of rotation ofthe mouthpiece cover 1220 with respect to the first actuator housingpart 1216 from the rest position to the primed position are shown. Thesecond housing part 1217 is omitted for clarity. In FIG. 32e , themouthpiece cover has been rotated by an angle A of −90 degrees, and thelug 1438 has moved a distance D1 from its rest position (shown in hiddenline). In this position, the inhaler is unuseable because the mouthpiececover would clash with the user's face. In FIG. 32f , the mouthpiececover 1220 has been rotated by angle an B of approximately −135 degrees.In this position, the lug 1438 has been moved downwards by a totaldistance D2, and the spring 1214 has been fully tensioned (i.e. withsufficient energy to actuate the mechanism). The final phase of movementfrom FIGS. 32f to 32g , i.e. to an angle C of 180 degrees, moves the lug1438 to a total displacement of D3, although it will be noted that dueto the curved path of the lug 1438 the distance from D2 to D3 is minimal(and as mentioned, the spring 1214 has already been fully tensioned).Therefore if the user tried to use the inhaler at any point between D2and D3, it would operate fully.

Referring to FIG. 32c , initially this downward force on the spring 1214acts to draw the piston 1208 downwards (the piston 1208 and spring 1214are attached). Because downward movement of the cylinder 1206 is notresisted at this stage, it also moves downwards as shown in FIG. 32c dueto gravity and the friction of the o-ring 1218, as well as due to airflow resistance through the air hole. The transfer 1212 remainsstationary at this point, as it abuts the canister 51. As the top of thespring 1214 moves downwards along axis X, the spring 1214 and thetransfer 1212 start to move apart due to the fact that the transfer legs1302 can slide in the leg openings 1340.

This initial motion occurs until, as shown in FIG. 32d , the taperedsurfaces 1252 of the piston teeth 1250 abut the first tapered ends 1282of the inner collar teeth 1280. As with the earlier embodiment, thepiston 1208 and the collar 1210 form a clutch for transfer of the springforce to the canister. At this point, a downward force is exerted on thecollar 1210 which cannot move due to the abutment of the transfer 1212and the canister 51 (held in place by the trigger abutment). The taperangles of the piston teeth 1250 and inner collar teeth 1280 are shallowsuch that a vertical force is produced without sufficient rotationalforce about the axis to overcome friction and rotate the collar 1210.

Therefore the spring shaft 1320 can no longer move due to a load pathbeing established through the piston 1208 onto the collar 1210, thetransfer 1212 and the canister 51. As the mouthpiece cover 1220continues to be rotated, the spring 1214 stretches to store potentialenergy. Once the mouthpiece cover 1220 is in the position shown in FIG.32a , the spring is “primed”.

3. Fired Condition

When the user wishes to dispense the medicament, a trigger mechanism(which is not described here) is fired in which the trigger abutment ismoved such that downward motion of the canister 51 is no longerinhibited. Previously, the canister 51 was resisting downward movementof the transfer 1212, which in turn was holding up the piston 1208 andtherefore the upper end of the spring 1214 (under tension). Release ofthe canister 51 releases the transfer 1212, collar 1210 and piston 1208to move downwards, pulled by the tensile force of the spring 1214 on thepiston 1208. The spring force Fs is transferred from the spring 1214,through the piston 1208 into the collar 1210 (i.e. through the clutchformed by the piston 1208 and collar 1210) and to the transfer 1212. Asthe stored energy in the spring 1214 is released, it serves to push thevalve stem 58 onto the valve stem abutment. This also acts against thebias of the valve spring within the valve 54 to open the canister 51 andrelease a dose of medicament.

At this point, a spring force Fs is being applied to the canister 51against the bias of a valve spring force Fv (FIG. 33).

As the collar 1210 moves downwards, the tapered surfaces 1294 of eachouter collar tooth 1292 engage the tapered surfaces 1232 of the teeth1228 of the actuator ring 1204. This acts to rotate the collar 1210about the axis X in direction+R and begin to move the clutch formed bythe piston 1208 and the collar 1210 to a released condition.

4. Auto-Release Condition

At a predetermined angle of rotation of the collar 1210 relative to thepiston 1208 (which cannot rotate because it is attached to the spring1214), the clutch formed by the collar 1210 and piston 1208 becomesdetached (or released) in a linear sense. This is because the innercollar teeth 1280 can eventually move through the gaps between thepiston teeth 1250 allowing relative linear movement between the piston1208 and collar 1210 (see FIG. 34). This breaks the load path betweenthe spring 1214 and the canister 51.

5. Can Reset Condition

The system is now separated into two sub-assemblies which encounteropposing forces Fs and Fv. Reference is made to FIG. 34.

On one hand, the return force of the spring in the canister valve Fvapplies an upward force on the transfer (via the canister 51) which inturn lifts the collar 1210 away from the actuator ring 1204. The collar1210 supports the cylinder 1206 which is also raised upwards.

On the other hand, the tensile force Fs remaining in the spring 1214acts to draw the piston 1208 downwards. Therefore, as the canister 51resiles to its rest (unactuated) position, its motion is controlled bythe separation of the piston 1208 and cylinder 1206. As mentioned above,relative motion of the piston and cylinder is controlled by ingress ofair into the air leak hole 1240. As such, the return of the canister(i.e. the timing of the return of the canister) is controlled, avoidingthe aforementioned problems.

6. Return to Rest Condition

The user rotates the mouthpiece cover 1220 back to its original positon,which has the effect of (with reference to FIG. 32e ) drawing the lug1438 upwards and lifting the spring 1214. This motion re-engages thepiston 1208 into the cylinder 1206. The shape of the air leak hole 1240provides a higher coefficient of discharge for air egress, compared tothat for air ingress described above.

As the top of the spring 1214 moves towards the collar 1210, the taperedsurface 1344 of each spring tooth 1342 engages the tapered second end1284 of one of five of the inner collar teeth 1280 to further rotate thecollar 1210. The rotation is such that the inner collar teeth 1280 arepositioned directly below the piston teeth 1250, and the outer collarteeth 1292 are positioned above the actuator ring teeth 1228 ready forthe next operation.

The Third Embodiment

Turning to FIGS. 35 to 50, a third pMDI 2150 according to an embodimentof the present invention is shown. The pMDI 2150 comprises a housing oractuator 2155 containing a canister 51 (FIG. 36). The canister 51contains a medicament formulation. It will be understood that thecanister is of the same type as the canister 51 described with referenceto FIG. 1 and comprises a can with a metering valve. The canister sitswithin the housing 2155. The pMDI 2150 has a stem socket and a triggerassembly that allows downward movement of the canister relative to thevalve's stem portion as described earlier in the detailed description,when the patient inhales through the mouthpiece. The stem socket andtrigger assembly have been omitted from FIG. 36 for clarity of thedrawing.

The pMDI 2150 comprises a portion in the form of a patient port 2157(e.g., in the form of a mouthpiece) that defines an inspiration orifice(or an air outlet). Such a patient port of an inhaler is sometimesreferred to herein as a “mouthpiece” for simplicity. However, it shouldbe understood that such mouthpieces can instead be configured to benosepieces of nasal inhalers and that the present disclosure can equallyapply to nasal inhalers even where not specifically mentioned herein.

The housing 2155 also comprises an upper section 2202 that comprises areset mechanism according to an embodiment of the present invention.

Referring to FIG. 36, an exploded view of the reset mechanism isprovided. The reset mechanism comprises an actuator ring 2204, acylinder 2206, a piston 2208, a transfer collar 2210, a spring 2214, asleeve 2400, a spring abutment 2212, a first actuator body part 2216, asecond actuator body part 2217, an o-ring 2218 and a mouthpiece cover2220.

With reference to FIG. 37, the actuator ring 2204 is a unitarycylindrical body constructed from a moulded plastics material having afirst, upper, edge 2222 and a second, lower, edge 2224. The first edge2222 defines a series of twelve axially extending teeth 2228. Each tooth2228 comprises a generally triangular formation at its free end, havinga straight axial edge 2230 and a tapered surface 2232 (extending bothaxially and circumferentially) which meet at end flat 2234. Each tooth2228 is separated at the edge 2222 by an inter-tooth gap 2236. Thesecond edge 2224 defines a pair of opposed curved recesses 2226. Betweenthe recesses 2226 there are provided elongate, circumferentiallyextending slots 2227 through the wall of the actuator ring 2204.

With reference to FIG. 38, the cylinder 2206 is a unitary cylindricalbody constructed from a moulded plastics material. The cylinder isclosed at a first, upper, end 2238 and open at a second, lower, edge2241. In the centre of the upper closed end 2238 there is provided aco-axial air leak hole 2240. The air leak hole 2240 is sized to providethe technical effect described below (damping) and as such the exactsize can be determined by the skilled technician. As with the air leakholes 240 and 1240 the air leak hole 2240 is tapered to decrease in areafrom the interior of the cylinder 2206 to the exterior of the cylinder2206. This results in a higher coefficient of discharge for fluidexiting the cylinder through the hole 2240 than air entering thecylinder through the hole 2240.

With reference to FIGS. 39a and 39b , the piston 2208 is shown. Thepiston 2208 is a unitary moulded plastics component. The piston 2208comprises a generally cylindrical piston body 2242 and a piston head2244 at one end thereof.

The body 2242 is a hollow cylinder having a first, upper, end 2246 atwhich the piston head 2244 is located, and a second, lower end 2248which is open. The body 2242 defines twelve identical, equally spaced,axially extending teeth 2250 on its outer surface. Each tooth 2250extends from the first end 2246 towards the second end 2248 (althoughthe teeth only extend part-way along the body 2242). The teeth 2250 eachterminate at a free end that defines a tapered surface 2252 extendingboth circumferentially and axially. The body 2241 further defines sixinwardly protruding elongate axial ribs 2470.

The piston head 2244 comprises a circular piston end cap 2256 having aradial edge 2258. The end cap 2256 is positioned at the first, upper,end 2246 of the body 2242. The head 2244 comprises an o-ring receivingchannel section 2260 extending axially towards the second end 2248 ofthe body 2242. The o-ring receiving channel section 2260 is formed bythe radial edge 2258 of the cap 2256 and a radial edge 2262 of anannular ring section 2264. On the underside of the end cap 2256 (i.e.the surface facing the interior of the body 2242) there is provided acentral axially extending shaft 2266 having two wings 2267 definedthereon.

Turning to FIG. 40, the o-ring 2218 is shown. The o-ring 2218 is astandard component and is constructed from an elastomeric materialdesigned to form a fluid seal against plastics material.

Referring to FIGS. 41a and 41b , the transfer collar 2210 is shown. Thetransfer collar 2210 combines the functionality of the collars 210, 1210and the transfers 212, 1212 of the first and second embodiments.Therefore the transfer collar 2210 effectively comprises a transfer anda collar in one unitary component. The transfer collar 2210 is a unitarymoulded plastics component.

The transfer collar 2210 comprises a cylindrical shaft 2270, and anannulus 2272. The shaft 2270 has a first, upper, end 2274 and a second,lower, end 2276. The shaft 2270 defines a series of twelve equallyspaced outer shaft teeth 2278 and series of twelve equally spaced innershaft teeth 2280. The outer shaft teeth 2278 extend from the first end2274 to the second end 2276. The inner shaft teeth 2280 each define atapered first, upper, end 2282 approximately midway along the shaft 2270and join the annulus 2272 at the lower end.

The annulus 2272 extends both inwardly and outwardly of the second endof the shaft 2270. The annulus 2272 comprises a first, upper surface2286 and a second, lower surface 2288. The annulus 2272 defines an outerrim 2290. At the outer rim 2290 there are positioned twelve outer collarteeth 2292. Each outer collar tooth 2292 extends radially outwardly andaxially downwards away from the second surface 2288. Each outer collartooth 2292 is tapered becoming narrower as it extends from the secondsurface 2288. Each tooth 2292 defines a tapered or ramped surface 2294and a flat, axial surface 2296 which meet at an end flat 2298.

Extending from the annulus 2272 away from the shaft 2270 there areprovided three equally spaced, axially extending legs 2302. Each leg2302 has a free end 2312 and a small ramp 2314 extending between the legand the annulus 2272, the ramp 2314 being defined by a tapered surface.Each ramp 2314 is positioned on one side of the respective leg 2302.

Referring to FIGS. 42a and 42b the sleeve 2400 is shown in detail. Thesleeve 2400 is a unitary, moulded, plastics component. The sleeve 2400comprises a cylindrical sleeve body 2318 and a sleeve shaft 2320projecting therefrom.

The sleeve body 2318 is generally cylindrical having a first, upper, end2322 and a second, lower, end 2324. The sleeve body 2318 defines firstand second opposed slots 2330 through the wall of the body 2318. Eachslot 2330 has a tapered end 2331 and a curved end 2332. The curved ends2332 face each other. The tapered ends 2331 result in the slots beingshorter at the interior surface of the sleeve body 2318 than at theexterior surface of the sleeve body 2318.

The first end 2322 of the body 2318 terminates in an annular surface2338 that defines three leg openings 2340. Each leg opening 2340 isshaped as a circle-segment.

The sleeve shaft 2320 extends from the centre of the annular surface2338 and is constructed as a hollow cylinder. The sleeve shaft 2320 hasa first, upper end 2350 having a coaxial opening 2351 and a second,lower, end 2352 where it joins the annular surface 2338. The sleeveshaft 2320 has six axially extending equally spaced grooves 2354 whichextend axially from the first end 2350 to the second end 2352.

Referring to FIGS. 43a and 43b , the spring abutment 2212 is shown. Thespring abutment 2212 comprises a shaft 2460 and an overhanging head 2462to define a shoulder 2463 therebetween. The shaft 2460 is generallycylindrical and defines an opening 2464 which is generally circularhaving two opposed wings 2466. The head 2462 defines an opening 2468 atits centre.

Referring to FIG. 44, the spring 2214 is shown, which is a metalcompression spring (shown in its rest state).

Referring to FIGS. 45a and 45b , the actuator body parts 2216 and 2217are shown in detail in exploded form.

The first actuator body part 2216 is a unitary, moulded plasticscomponent which is generally elongate and concave having a curved wall2402, a first end 2404 and a second end 2406 opposite the first. On theinterior side of the concave wall 2402 there is provided a downwardlyfacing transfer collar abutment 2408 in the form of a shoulder, and anactuator ring abutment 2410 in the form of a circumferentially andradially inwardly extending rib. The wall 2402 also comprises twoparallel side panels 2414 extending from either side thereof. Each sidepanel 2414 is flat and defines an opening 2416 therein. Each opening2416 is generally circular having two opposed wings 2418, 2420 extendingtangentially therefrom. The wall 2402 also defines four longitudinallyextending stiffening ribs 2422. Both openings 2416 lie on a mouthpiececover axis M.

The second actuator body part 2217 is a unitary, moulded plasticscomponent which is generally elongate and concave having a curved wall2424, a first endwall 2426 and a second endwall 2428 opposite the first.On the interior side of the concave wall 2424 there is provided adownwardly facing collar abutment 2430 in the form of a shoulder. Thewall 2424 also defines four longitudinally extending stiffening ribs2434.

Referring to FIG. 46, the mouthpiece cover 2220 is shown in more detail.The mouthpiece cover 2220 is a unitary, moulded plastics component. Themouthpiece cover 2220 comprises a cap 2374 and two arms 2376 that aremirror images of each other.

The cap 2374 is an internally concave structure suitable for sealing amouthpiece of the inhaler patient port 2157. The cap 2374 has a closedend 2378 and an open end 2380. The cap 2374 defines a pair of opposedsidewalls 2382 from which the arms 2376 extend proximate the open end2380.

Each arm 2376 is an elongate, generally planar structure extending to afree end 2384. At the free end 2384, and on an inwardly facing surfaceof each arm 2376 there is provided a cam 2386. The cam 2386 comprises agenerally cylindrical body 2388 having two tangentially extending,opposed wings 2436. The cam also defines an inwardly projecting cam lug2438 which is off-centre on the cylindrical body 2388.

Assembly

The components described above are aligned on a main axis X. Referringto FIGS. 47a to 47d (as well as the exploded view of FIG. 36), thesystem is shown in its assembled state, in a rest condition (used forstorage and generally when not in operation). The view in FIG. 47a is insection A of FIG. 35. The views in FIGS. 47b and 47c are approximatelyin direction B of FIG. 35, but with the first actuator body part 2216removed in the case of FIG. 47b , and with both actuator body partsremoved in FIG. 47c . The view of FIG. 47d is a section in theapproximate direction of D in FIG. 47 a.

The transfer collar 2210 is assembled with the sleeve 2400 by passingthe legs 2302 into the openings 2340. Referring to FIG. 47d , the legs2302 and ramps 2314 are fully engaged in the openings 2340 of the sleeve2400.

Referring to FIG. 47a , the spring 2214 is inserted into the sleeveshaft 2320 so that it abuts the upper end 2350 thereof. The springabutment 2212 is then inserted into the spring 2214 such that the end ofthe shaft 2460 extends into the opening 2351 in the sleeve shaft 2320.The spring 2214 is thereby trapped by the shoulder 2463 of the springabutment 2212. The spring abutment can slide relative to the sleeve 2400along the axis X to compress the spring 2214. The sub-assembly of thesleeve 2240, spring 2214 and spring abutment 2212 form an energy storagearrangement.

The piston 2208 is slid over the sleeve shaft 2320 such that the pistonshaft 2266 engages and mates with the opening 2464 on the springabutment 2212. The end of the piston shaft 2266 abuts the head 2462 ofthe spring abutment 2212 and is bonded thereto such that the piston 2208and the spring abutment are fixed.

It will also be noted that the inwardly extending ribs 2470 of thepiston 2208 engage the grooves 2354 on the exterior of the sleeve shaft2320 to facilitate relative sliding of the piston—spring abutmentsub-assembly relative to the sleeve 2400.

The o-ring 2218 is assembled into the groove 2260 on the piston 2208,and the piston 2208 is inserted into the open end of the cylinder 2206to form a seal therewith. The o-ring 2218 seals against the innersidewall of the cylinder 2206 such that axial movement of the pistonresults in airflow through the air leak hole 2240. As such, relativemotion of the piston 2208 and cylinder 2206 is damped. Further, becausethe hole 2240 is tapered, movement of the piston 2208 into the cylinder2206 is resisted less than movement of the piston 2208 out of thecylinder 2206. In other words, separation of the piston 2208 andcylinder 2206 is damped more than movement of the piston 2208 into thecylinder 2206.

The assembly of the transfer collar 2210, sleeve 2400, spring 2214,spring abutment 2212, piston 2208, o-ring 2218 and cylinder 2206 ispositioned within the actuator body parts 2216, 2217 and can moveaxially relative thereto.

The actuator ring 2204 is then positioned within the actuator body parts2216, 2217 and held stationary relative thereto by engagement of theslot 2227 with the actuator ring abutment 2410.

In this rest position, the outer collar teeth 2292 face downwardly asshown in FIG. 47b to face the tapered edges 2232 of the actuator ringteeth 2228. The teeth 2292, 2228 are offset. The upper surfaces 2282 ofthe inner collar teeth 2280 face the downwardly facing surfaces 2252 ofthe piston teeth 2250. The upper surface of the teeth 2292 of thetransfer collar 2210 abut the collar abutments 2408, 2430 of therespective actuator body parts 2216, 2217.

The mouthpiece cover 2220 is snap-fitted onto the first actuator bodypart 2216 in the same manner as with the second embodiment (and as suchwill not be described in detail here). It will be noted that instead ofengaging the spring 2214, the cam lugs 2438 engage the slots 2330 on thesleeve 2400 (FIG. 47c ). The provision of the curved recesses 2226 onthe actuator ring 2204 facilitate this engagement resulting in a compactassembly.

In the rest position, the mouthpiece cover 2220 covers the inhalermouthpiece (see FIG. 35).

Operation

The pMDI 2150 is used as follows. The operation of the pMDI 2150 is bestdescribed as passing through a number of operational conditions orstages as will be described below.

1. Rest Condition

The rest condition is shown in FIGS. 35, 36 and 47 a to 47 d. In thiscondition, a canister 51 having a can 53 and a metering valve 54 with avalve stem 58 is provided within the pMDI. The stem 58 abuts a stemabutment which is static within the pMDI 2150. In the rest condition,downward travel of the canister 51 is inhibited by a trigger abutmentwhich is part of a trigger assembly (not described here, but generallyknown in the art).

In this position, the canister 51 is positioned partly within the sleeve2400 (FIG. 47a ), and the free ends 2312 of the legs 2302 of thetransfer collar 2210 abut the bottom of the canister 51 (as it isinverted). The tapered surfaces 2294 of the outer collar teeth 2292 arealigned with, and facing, the tapered surfaces of the upwardlyprojecting teeth 2228 of the actuator ring 2204 (FIG. 47b ).

The spring 2214 is also in a rest position, and stores no energy. Asshown in FIG. 47a , the spring 2214 is at length S1. The piston 2208 andcylinder 2206 are fully engaged, with the sleeve shaft 2320 fullyengaged in the piston as shown in FIG. 47a . The piston teeth 2250 arespaced apart along axis X from the inner collar teeth 2280.

2. Primed Condition

Turning to FIGS. 48a to 48b , the mouthpiece cover 2220 has been rotatedabout the mouthpiece cover axis M, such that the lugs 2438 have moveddownwards in the housing and drawn the sleeve 2400 vertically downwards.

Referring to FIG. 48b , the sleeve 2400 produces a downward force alongaxis X on the spring 2214 (omitted for clarity from FIG. 48b ). This, inturn, draws the spring abutment 2212 downwards which in turn draws thepiston 2208 downwards. Because there is a resistance to separation ofthe piston 2208 and the cylinder 2206 (due to both the size of theopening 2240 and the o-ring 2218), the cylinder 2206 is also drawndownwards until it abuts the first end 2274 of the shaft 2270 of thetransfer collar 2210. At the same time, as shown in FIG. 48c , thetapered surfaces 2252 of the piston teeth 2250 abut the ends 2282 of theinner shaft teeth 2280.

It will be noted that the canister 51 is held in position by the triggermechanism, and as such the transfer collar 2210 cannot move downwards.Neither the cylinder 2206 nor the piston 2208 can move further downwardsas they are both supported by the transfer collar 2210.

Further movement of the mouthpiece cover 2220 to draw the sleeve 2400down compresses the spring to length S2 (FIG. 48b ). The spring therebystores the actuation energy for the canister 51.

As with the FIGS. 32e to 32g , the spring 2214 is fully compressed (i.e.with sufficient energy to actuate the mechanism) at an intermediateposition of the mouthpiece.

3. Fired Condition

When the user wishes to dispense the medicament, a trigger mechanism(which is not described here) is fired in which the trigger abutment ismoved such that downward motion of the canister 51 is no longerinhibited.

In the primed condition, the canister 51 was resisting downward movementof the transfer collar 2210, which in turn was holding up the piston2208 and therefore the lower end of the spring 2214 (under compression)via the spring abutment 2212.

Release of the canister 51 releases the transfer collar 2210 in adownward direction. Because the sleeve 2400 is held in position by themouthpiece cover 2220, the spring 2214 pushes the spring abutment-pistonassembly in a downwards direction, which in turn produces a downwardsforce on the transfer collar 2210 (due to the abutment of the teethshown in FIG. 48c ). The energy of the spring 2214 therefore acts tocompress the canister 51 by pushing the valve stem 58 onto the valvestem abutment. This also acts against the bias of the valve springwithin the valve 54 to open the canister 51 and release a dose ofmedicament.

At this point, a spring force Fs is being applied to the canister 51against the bias of a valve spring force Fv (FIG. 49).

Still referring to FIG. 49, as the transfer collar 2210 moves downwardsalong the axis X, the tapered surfaces 2294 of the outer collar teeth2292 engage the tapered surfaces 2232 of the teeth 2228 of the actuatorring 2204. This acts to rotate the transfer collar 2210 about the axis Xin direction+R and begins to move the clutch formed by the piston 2208and the transfer collar 2210 to a released condition.

4. Auto-Release Condition

At a predetermined angle of rotation of the transfer collar 2210relative to the piston 2208 (which cannot rotate) the clutch formed bythe transfer collar 2210 and piston 2208 becomes detached (or released)in a linear sense. This is because the inner collar teeth 2280 caneventually move through the gaps between the piston teeth 2250 allowingrelative linear movement between the piston 2208 and the transfer collar2210 (see FIG. 50). This breaks the load path between the spring 2214and the canister 51.

5. Can Reset Condition

The system is now separated into two sub-assemblies which encounteropposing forces Fs and Fv. Reference is made to FIG. 50.

On one hand, the return force of the spring in the canister valve Fvapplies an upward force on the transfer collar 2210 (via the canister51) such that it lifts away from the actuator ring 2204. The transfercollar 2210 supports the cylinder 2206 which is also raised upwards.

On the other hand, the compressive force Fs remaining in the spring 2214acts to drag the piston 2208 downwards. Therefore, as the canister 51resiles to its rest (unactuated) position, its motion is controlled bythe separation of the piston 2208 and cylinder 2206. As mentioned above,relative motion of the piston and cylinder is controlled by ingress ofair into the air leak hole 2240. As such, the return of the canister(i.e. the timing of the return of the canister) is controlled, avoidingthe aforementioned problems.

6. Return to Rest Condition

The user rotates the mouthpiece cover 2220 back to its originalposition, which has the effect of drawing the lugs 2438 upwards andlifting the sleeve 2400. This motion re-engages the piston 2208 into thecylinder 2206. The shape of the air leak hole 2240 provides a highercoefficient of discharge for air egress, compared to that of air ingressdescribed above.

Upward movement of the sleeve 2400 acts to fully engage the legs 2302within the leg openings 2340 of the sleeve 2400 such that the ramps 2314cause return/reciprocal rotation of the transfer collar 2210. Referringto FIG. 47d , when fired, the clutch release acts in direction +R. Uponreturn to rest the transfer collar is rotated back to its originalposition in direction −R by the ramps 2314. By contrast with the pMDIs150 and 1150, the transfer collar 2210 (unlike the collars 210, 1210)has a reciprocal rather than a continuously rotating motion. Therotation back to the original position realigns the tapered surfaces2252 of the piston teeth 2250 and the ends 2282 of the inner shaft teeth2280. In other words, the clutch is reset to a position in which axialforce can be transmitted from the spring to the canister ready for thenext operation.

The Fourth Embodiment

Turning to FIGS. 51 to 64, part of a fourth pMDI 3150 according to anembodiment of the present invention is shown. The pMDI 3150 comprises ahousing or actuator 3155 containing a canister 51 (FIG. 52). Thecanister contains a medicament formulation. It will be understood thatthe canister is of the same type as the canister 51 described withreference to FIG. 1 and comprises a can with a metering valve. Thecanister sits within the housing 3155.

The housing 3155 comprises a lower section 3200 having a tubular sleeveportion 3156 dimensioned to receive the canister, and a portion in theform of a patient port 3157 (e.g., in the form of a mouthpiece) thatdefines an inspiration orifice (or an air outlet).

The housing 3155 also comprises an upper section 3202 which comprisesthe reset mechanism according to an embodiment of the present invention.

Referring to FIG. 52, an exploded view of the upper section 3202 isprovided. The upper section comprises a cylinder 3206, a piston 3208, atransfer collar 3210, a spring 3214, an actuator body 3216, an o-ring3218 and a mouthpiece cover 3220.

With reference to FIG. 53, the cylinder 3206 is a unitary cylindricalbody constructed from a moulded plastics material. The cylinder isclosed at a first, upper, end 3238 and open at a second, lower, edge3241. The cylinder, unlike the embodiments above, has no leak hole.

Turning to FIG. 54, the o-ring 3218 is shown. The o-ring 3218 is astandard component and is constructed from an elastomeric materialdesigned to form a fluid seal against plastics material.

With reference to FIGS. 55a and 55b , the piston 3208 is shown. Thepiston 3208 is a unitary moulded plastics component. The piston 3208comprises a disc-like piston head 3244, a central shaft 3242, three legs3246 and three teeth 3248 extending axially therefrom.

The piston head 3244 comprises an o-ring receiving channel section 3260.

The central shaft 3242 extends axially from the head 3244, has a centralaxial bore 3250 as well as three axially extending slots 3251.

The legs 3246 are equally spaced around the shaft 3242 and are eachgenerally “L” shaped in cross section extending in an axial direction.

The teeth 3248 are equally spaced proximate the periphery of the head3244 and each defines a tapered surface 3247 at a free end thereof.

Referring to FIGS. 56a to 56c , the transfer collar 3210 is shown. Thetransfer collar 3210 is a unitary moulded plastics component. Thetransfer collar 3218 comprises an outer ring 3270 and an inner ring3272.

The outer ring 3270 is generally cylindrical and defines three equallyspaced external tabs 3274.

The inner ring 3272 is also generally cylindrical and is connected tothe outer ring 3270 by three equally spaced ribs 3276. The inner ring3272 defines three axially extending teeth 3280 each of which has atapered surface 3282. Adjacent each tooth the ring defines an axiallyextending recess 3284 each of which defines a tapered surface 3286.Protruding opposite to the teeth 3280 and the recesses 3284 there areprovided three transfer legs 3288 having free ends 3290. The recesses3284 extend partway into the transfer legs 3288.

Protruding radially inwardly from the inner ring 3272 there are providedthree arms 3292 having free ends 3294 which almost meet at the centre ofthe inner ring 3272. The arms 3292 are at the same circumferentialpositions as the ribs 3276.

Referring to FIG. 57, the spring 3214 is shown in detail. The spring3214 is a unitary, moulded, plastics component which acts as a unitaryenergy storage arrangement, in contrast to the pMDIs 1150, 2150 whichutilise multiple component energy storage arrangements.

The spring 3214 comprises a tubular spring body 3318 that is generallycylindrical, having a first, upper, end 3322 and a second, lower, end3324. The spring body 3318 has a first, upper, region 3326 and a second,lower region 3328.

The first region 3326 is axially extensible and resilient. This isachieved by forming a series of six rows of slot-like openings 3330through the wall of the body 3318. Each row comprises six openings 3330which are equally spaced around the circumference of the body 3318. Theopenings 3330 are formed such that the first region 3326 can beelastically extended, and will resile back to a rest condition as shownin FIG. 57. The second region 3328 comprises a first and second pair ofoutwardly extending, diametrically opposed pegs 3332, 3334 respectively.The pegs 3332, 3334 are cylindrical. The first pair of pegs 3334 ispositioned adjacent the first region 3326, and the second pegs arepositioned proximate the second end 3324.

The first end 3322 of the body 3318 terminates in a flat surface 3338that defines three leg openings 3340. Four axially extending flat springmembers 3342 are provided projecting from the surface 3338. Two of thespring members 3342 are provided as a pair, and as such, the springmembers are positioned in three groups (two individual members and onepair) equidistantly spaced. The members 3342 are generally rectangular.In the centre of the surface 3338 there is provided a locating pin 3344.

Referring to FIGS. 58a and 58b , the actuator body 3216 is shown indetail. FIG. 58b is in cross-section through plane B in FIG. 58a . Theactuator body 3216 comprises a first, upper, section 3356 and a second,lower, section 3358. The sections 3356, 3358 define a generally elongatehousing enclosing a cavity which is open at the lower end.

The first section 3356 is generally cylindrical having a first, upperend which is closed by an endwall 3360. Transfer collar abutments 3434are defined on the inner surface thereof, being axially extending ribshaving ends 3435.

The second section 3358 is generally rectangular in cross-section andjoins the first section 3356 via a pair of shoulders 3364. The secondsection 3358 has an open end 3366. A pair of opposed circular apertures3368 are disposed in opposing walls of the second section proximate theshoulders 3364. Each aperture 3368 defines a tangential notch 3370projecting outwardly. Both apertures lie on a mouthpiece cover axis M.Extending from each aperture 3368 along the respective interior sidewallof the second section 3358 there is provided a spring peg groove 3372.The spring peg grooves 3372 start from a position substantially oppositethe notch 3370 and extend axially within the second section 3358 to theopen end 3366.

Referring to FIG. 59, the mouthpiece cover 3220 is shown in more detail.The mouthpiece cover 3220 is a unitary, moulded plastics component. Themouthpiece cover 3220 comprises a cap 3374 and two arms 3376 that aremirror images of each other.

The cap 3374 is an internally concave structure suitable for sealing amouthpiece of the inhaler patient port 3157. The cap 3374 has a closedend 3378 and an open end 3380. The cap 3374 defines a pair of opposedsidewalls 3382 from which the arms 3376 extend proximate the open end3380.

Each arm 3376 is an elongate, generally planar structure extending to afree end 3384. At the free end, and on an inwardly facing surface ofeach arm 3376 there is provided a cam 3386. The cam comprises a lobe3387 which has an undercut portion.

The cam 3386, is similar in shape to the cam 386 and has an outer radiusand a peg-receiving notch 3390 which extends radially inwardly.

Assembly

All of the components described above are aligned on a main axis X.Referring to FIGS. 60a to 60c (as well as the exploded view of FIG. 52),the pMDI 3150 is shown in its assembled state, in a rest condition (usedfor storage and generally when not in operation).

The transfer collar 3210 and the spring 3214 are assembled by passingthe transfer legs 3288 into the leg openings 3340. Referring to FIG. 60cthe openings 3340 are longer than the legs 3288 and as such allow apredetermined degree of rotation (approximately 10 degrees) of thetransfer collar 3210 about the axis X relative to the spring 3214. Thespring members 3342 project through the inner ring 3272.

Referring to FIG. 60b , the piston 3208 is assembled with the transfercollar 3210 and spring 3214 by inserting the central shaft 3242 betweenthe free ends 3294 of the arms 3292 which enter the slots 3251. The arms3292 also abut the ends of the legs 3246 of the piston 3208. The axialbore 3250 mates with the locating pin 3344. The piston 3208 and spring3214 are bonded together.

The piston legs 3246 each abut a spring member 3342, with one leg 3246being trapped between two spring members 3342 as visible with respect tothe top left leg in FIG. 60b . Referring to FIG. 60a , the taperedsurfaces 3247 of the teeth 3248 of the piston 3208 abut the taperedsurfaces 3282 of the teeth 3280 of the transfer collar 3210.

Referring to FIG. 60a , the o-ring 3218 is positioned within the groove3260 on the piston 3208 and the cylinder 3206 is assembled over thepiston 3208. The lower edge 3241 of the cylinder 3206 abuts the top ofthe outer ring 3270 of the transfer collar 3210.

The assembly is positioned within the actuator body 3216 with theexternal tabs 3274 of the transfer collar 3210 abutting the transfercollar abutments 3434 (FIG. 60b ). Pegs 3332, 3334 of the spring 3214are slidably engaged in the spring peg grooves 3372. The mouthpiececover 3220 is assembled onto the actuator body 3216 and rotated intoposition. It will be noted that as with the earlier embodiments, themouthpiece cover 3220 can only be assembled in one rotational positionsuch that the cams 3386 can engage the apertures 3368. Like themouthpiece 220, assembly can only be achieved before the lower part ofthe housing and patient portion is provided (reference is made to FIGS.13d to 13e and the accompanying description). The pMDI 150 achieves thiswith a retaining flange 370 whereas the pMDI 3150 utilises a shaped cam3390 which can only enter the aperture 3368 in one rotational positionthereof due to the presence of the lobe 3387. Once engaged, because thelobe 3387 is undercut, the mouthpiece cover 3220 can rotate about themouthpiece cover axis M.

In the rest position, like the mouthpiece cover 220, the notch 3390traps the upper peg 3332 of the spring 3214.

Operation

The pMDI 3150 is used as follows. The operation of the pMDI 3150 is bestdescribed as passing through a number of operational conditions orstages as will be described below.

1. Rest Condition

The rest condition is shown in FIGS. 60a to 60c . In this condition, acanister 51 is provided within the pMDI. As with previous embodiments, astem of the canister 51 abuts a stem abutment that is static within thepMDI 3150. In the rest condition, downward travel of the canister 51 isinhibited by a trigger abutment that is part of a trigger assembly (notdescribed here, but generally known in the art).

In this position, the canister 51 is positioned partly within the spring3214 (FIG. 60a ), and the free ends 3290 of the legs 3288 of thetransfer collar 3210 abut the bottom of the canister 51 (as it isinverted). The transfer collar 3210 supports the piston 3208 which inturn supports the cylinder 3206. The spring 3214 is held up by theengagement of the peg 3332 with the notch 3390 on the mouthpiece cover3220. The spring 3214 is in a rest position, and stores no energy.

2. Primed Condition

In this condition, the mouthpiece cover 3220 has been rotated about themouthpiece cover axis M, such that the first pegs 3332 have been drawninto the spring peg groove 372. This action tends to apply a tensileforce to the first region of the spring 3326, drawing it downwards.

The movement of the mouthpiece cover 3220 to extend and thereby actuatethe spring is the same as with the first embodiment, i.e., a 90 degreerotation of the mouthpiece cover 3220 urges the peg 3332 almost fullyinto the groove 3372. At this position, the inhaler is unusable becausethe mouthpiece cover 3220 would clash with the user's face if they triedto place their mouth over the mouthpiece.

Rotation to approximately 135 degrees rotates the cam 3386 to an extentthat the peg 3332 is almost fully within the groove 3372. At this point,because the notch 3390 has cleared the peg 3332, further rotation of themouthpiece cover 3220 has no effect on the linear position of the peg3332. At this position it is still not possible to use the inhalerbecause the mouthpiece cover is in a position where it would clash withthe user's face.

The final, primed position of the mouthpiece cover is at an angle of 180degrees which only serves to move the mouthpiece 3220 out of the way(the spring is not extended any further). As with the first embodiment,this lost motion ensures that should a user attempt to use the inhalerwhen the mouthpiece cover 3220 is not fully rotated, the inhaler willoperate as normal because the spring 3214 is fully energised.

Initially this downward force on the spring 3214 acts to draw the piston3208 downwards (the piston 3208 and spring 3214 are attached). Downwardmotion of the piston is resisted by the abutment of the piston teeth3246 with the transfer collar teeth 3280, and the transfer collar 3210is held in position by the canister 51 which is held up by the triggermechanism. Although the teeth abut at tapered surfaces (producing atorque in direction −R) rotation of the transfer collar 3210 is resistedby abutment of the external tabs 3274 of the transfer collar 3210 withthe transfer collar abutments 3434 of the actuator body 3216.

Downward movement of the cylinder 3206 is resisted by the piston and bythe abutment of the cylinder 3206 with the transfer collar 3210.

The only movement between the rest and primed conditions is thereforeextension of the spring 3214.

3. Fired Condition

When the user wishes to dispense the medicament, a trigger mechanism(which is not described here) is fired in which the trigger abutment ismoved such that downward motion of the canister 51 is no longerinhibited.

Release of the canister 51 releases the transfer collar 3210 and piston3208 to move downwards, pulled by the tensile force of the spring 3214on the attached piston 3208. The cylinder 3206 has also moved downwardsas shown in FIG. 61a . As the stored energy in the spring 3214 isreleased, it serves to push the valve stem onto the valve stem abutment.This also acts against the bias of the valve spring within the valve toopen the canister 51 and release a dose of medicament. Because the forcefrom the spring 3214, Fs, exceeds that from the valve, Fv, at thisjuncture, dose release is ensured (FIG. 61).

4. Auto-Release Condition

The external tabs 3274 of the transfer collar 3210 eventually clear thefree ends 3435 of the transfer collar abutments 3434. This allows thetransfer collar 3210 to rotate about the axis X in direction −R (FIG.62a ). This rotation occurs due to the torque created by the abutment ofthe tapered surfaces 3247 of the piston teeth 3248 abutting the taperedsurfaces 3282 of the transfer collar teeth 3280 (FIG. 60a ).

As shown in FIG. 62a , the arms 3292 are still engaged with the shaft3242 and abut the legs 3246 and as such need to elastically andresiliently deform as the transfer collar 3210 rotates (the hidden linesshow their undeformed state).

At a predetermined angle of rotation of the transfer collar 3210relative to the piston 3208 (which cannot rotate, because it is bondedto the spring 3214, which itself cannot rotate) the transfer collar 3210and piston 3208 become detached (or released) in a linear sense. Inother words, as the collar 3210 rotates, the clutch formed by the collar3210 and piston 3208 is released. This is because the piston teeth 3248can eventually move into the recesses 3284 in the transfer collar 3210allowing relative linear movement along the axis X between the piston3208 and transfer collar 3210 as shown in FIG. 62 b.

5. Can Reset Condition

The release of the clutch now separates the system into twosub-assemblies which encounter opposing forces. Reference is made toFIG. 63.

On one hand, the return force of the spring in the canister valve Fvapplies an upward force on the transfer collar 3210 (via the canister51), which in turn lifts the transfer collar 3210 and also the cylinder3206.

On the other hand, the tensile force Fs remaining in the spring 3214acts to draw the piston 3208 downwards. Therefore, as the canister 51resiles to its rest (unactuated) position, its motion is controlled bythe separation of the piston 3208 and cylinder 3206. The vacuum (or atleast very low air pressure) created within the cylinder damps thereturn, controlling the speed at which the canister returns to its reststate.

The piston 3208 and transfer collar 3210 become fully engaged. Thetransfer collar ends up in the rest position in a vertical (axial)sense, although cannot rotate back under the resilience of the arms 3292as it is held, unable to rotate, by the piston 3208.

6. Return to Rest Condition

The user rotates the mouthpiece cover 3220 back to its original positon,which has the effect of drawing the first peg 3332 of the spring 3214upwards towards its starting (rest) position. This motion allows there-engagement of the piston 3208 into the cylinder 3206, which is partlyurged by the vacuum/low pressure in the cylinder. The separation of thepiston 3208 and the transfer collar 3210 allows the transfer collar 3210to rotate under the bias of the arms 3292 to its original rotationalposition whereby the piston teeth 3248 and the transfer collar teeth3280 are in vertical abutment as shown in FIG. 64.

It will be understood that variations in the above embodiments fallwithin the scope of the claims. For example, the inhaler does not haveto be a pMDI, and may be a DPI or other type of inhaler.

In an aspect, an embodiment of the present invention can be applied toinhaler devices such as pressurized metered dose inhalers, dry powderinhalers or portable nebulizers. It is particularly preferred that theinhaler device is a pressurized metered dose inhaler (pMDI), since themechanisms can provide suitable leverage for a patient to apply theright amount of force in the right direction typical for actuating pMDIvalves. In the case of dry powder inhalers, where there is a store ofdrug in a reservoir that is sampled upon priming or actuation of thedevice, the reservoir may be a canister or other container. A dose maybe dispensed from the container using an energy storage arrangement,either to position the dose for inhalation by a user or to aerosolize adose using the energy of the energy storage arrangement. In the case ofportable nebulizers, a typical such device is disclosed in patent no.U.S. Pat. No. 5,964,416. In FIG. 6a, 6b of that patent, a container issurrounded by a spring. A cover for the patient port could be configuredto drive the spring by using a mechanism similar to one disclosed hereinfor pressurized metered dose inhalers.

In an aspect, an embodiment of the present invention can be applied toinhaler devices such as pressurized metered dose inhalers, dry powderinhalers or portable nebulizers, because the mechanism to generate thedrug aerosol does not generally limit the arrangement of the mouthpiececover.

In an aspect, an embodiment of the present invention can be applied toinhaler devices such as pressurized metered dose inhalers, dry powderinhalers or portable nebulizers, in similar ways to those of the firstaspect. Here, a portable nebulizer shown in patent application no.US2009/0114925A1 has an axially tensioned drive spring that surrounds acontainer.

1. An inhaler comprising: a housing having a patient port and a cover rotatable about a cover axis between a closed position in which the cover covers the patient port, and an open position in which the patient port is accessible; an energy storage arrangement within the housing, the energy storage arrangement comprising a resilient member and defining a void for receiving a medicament container; in which the cover axis intersects the void, and in which the cover is configured to drive the resilient member to store energy therein upon rotation from the closed position towards the open position.
 2. The inhaler according to claim 1, in which a cam is provided between the cover and the energy storage arrangement so as to produce a linear force on the resilient member upon rotation of the cover.
 3. The inhaler according to claim 2, in which the cam comprises a cam member driven by the cover, the cam member being offset from the cover axis, in which the cam member is engaged with an engagement formation of the energy storage arrangement.
 4. The inhaler according to claim 3, in which the resilient member defines the engagement formation.
 5. The inhaler according to claim 4, in which the resilient member defines the void.
 6. The inhaler according to claim 5, in which the resilient member is a generally tubular member having a resilient portion.
 7. The inhaler according to claim 6, in which the resilient portion is an extensible portion configured to store energy in tension.
 8. The inhaler according to claim 7, in which the resilient portion comprises a cylindrical body having a plurality of openings defined therein.
 9. The inhaler according to claim 8, in which the plurality of openings are arranged in a plurality of offset rows.
 10. (canceled)
 11. The inhaler according to claim 3, in which the energy storage arrangement comprises a sleeve arranged to transfer force from the cover to the resilient member.
 12. The inhaler according to claim 11, in which the engagement formation is defined on the sleeve. 13-19. (canceled)
 20. An inhaler comprising: a first housing part; a patient port; and, a cover mounted to the first housing part via a mating formation so as to be rotatable about a cover axis within an operational range of movement between a closed position in which the cover covers the patient port, and an open position in which the patient port is accessible; and, in which: the mating formation is configured so as to permit assembly of the housing part and cover in at least one predetermined rotational position of the cover which is outside the operational range of movement; and, the cover is blocked from entering the predetermined rotational position or range of positions by a further component of the inhaler.
 21. The inhaler according to claim 20, in which the further component is a second housing part.
 22. The inhaler according to claim 21, in which the first housing part and the second housing part define a volume for receiving a medicament container.
 23. The inhaler according to claim 22, in which the further component comprises the patient port. 24-30. (canceled)
 31. An inhaler comprising: a housing having a patient port and a cover rotatable about a cover axis between a closed position in which the cover covers the patient port, and an open position in which the patient port is accessible; an extensible resilient structure within the housing defining a void for receiving a medicament container; in which the cover is configured to drive the resilient structure in tension to store energy therein upon rotation from the closed position towards the open position.
 32. The inhaler according to claim 31, in which a cam is provided between the cover and the resilient structure so as to produce a linear force on the resilient structure upon rotation of the cover.
 33. The inhaler according to claim 32, in which the cam comprises a cam member driven by the cover, the cam member being offset from the cover axis, in which the cam member is engaged with a receiving formation connected to the resilient structure.
 34. The inhaler according to claim 33, comprising a sleeve arranged to transfer force from the cover to the resilient structure, in which the sleeve surrounds at least part of the resilient structure, which sleeve is connected to the resilient structure at a position spaced apart from the cover axis.
 35. The inhaler according to claim 34, in which the receiving formation is provided on the sleeve. 36-43. (canceled) 